;-NRLF 


THIS  IS  THE  PROPERTY  OF 


If  thou  art  borrowed  by  a  friend, 
Right  welcome  shall  he  be 

To  read,  to  study,  not  to  lend, 
But  to  return  to  me. 


Not  that  imparted  knowledge  doth 

Diminish  learning's  store, 
But  books,   I  find,  if  often  lent, 
Return  to  me  no  more. 


Slowly;   Pause  Frequently;  Think  Seriously;  Analyze  Carefully; 
Reason  Logically;  Keep  Cleanly;  Return  Duly, 


WITH   THK   CORNERS    OF    THK   LEAVES   NOT   TURNED    DOWN. 


MEMCAL 


Gift  of 


Dr.  Mary  Martin 


PRACTICAL 


DISSECTIONS 


RICHARD  M.  HODGES,  M.D., 

FORMERLY  DEMONSTRATOR  OF  ANATOMY  IN  THE  MEDICAL  DEPABTMENT  OF  HARVARD 
UNIVERSITY. 


SECOND  EDITION,  THOROUGHLY  REVISED. 


PHILADELPHIA: 

HENRY     C .     LEA 

1867. 


"  '**•  "  •'"••         :  :*::  : 


•*..**    >  *  *• 
»»  •.»    »..*  ,    I 


Entered  according  to  Act  of  Congress,  in  the  year  1867,  by 

R.    M.    HODGES, 
in  the  Clerk's  Office  of  the  District  Court  of  the  District  of  Massachusetts. 


PHTLAT)KIjPHIA  : 
COLLINS,  PE1NTKK,  705  JAYNK  STREKT. 


1  £ 


NOTE  TO  THE  SECOND  EDITION. 


IN  revising  the  following  pages  no  alterations  have 
been  made,  other  than  those  which  experience  in  their 
use  has  suggested.  It  has  been  the  Author's  endeavor 
to  make  the  descriptions  as  clear  and  concise  as  possi- 
ble, rather  than  to  add  to  their  details ;  and  to  render 
the  volume,  in  all  respects,  more  deserving  of  the  favor 
it  has  received. 

The  few  pages  on  Anatomical  Landmarks  were  sug- 
gested by,  and  to  a  small  extent  taken  from,  an  article 
by  Mr.  Luther  Holden,  contained  in  the  second  volume 
of  the  "  Eeports  of  St.  Bartholomew's  Hospital." 

• 

BOSTON,  February,  1867. 


36411 


PREFACE. 


THE  "  Practical  Dissections"  is  not  a  Treatise  on 
Anatomy,  nor  in  any  way  a  substitute  for  one.  It  is 
intended  to  be  simply  a  practical  guide  in  the  ordinary 
dissections  of  the  Medical  Student,  describing  on  the 
same  page,  and  in  connection,  the  muscles,  nerves, 
arteries,  veins,  or  other  structures  which  are  conjointly 
exposed,  and  only  so  far  as  exposed,  in  dissecting  any 
one  of  the  parts  into  which  the  dead  subject  is  usually 
divided.  Remembering  that  "the  smallness  of  the  size 
of  a  book  is  always  its  own  recommendation,  as,  on  the 
contrary,  the  largeness  of  a  book  is  its  own  disadvan- 
tage, as  well  as  the  terror  of  learning,"  all  Minute 
Anatomy,  and  the  details  of  arterial  distribution,  beyond 
what  an  ordinary  injection  exhibits,  or  of  nervous  rami- 
fications which  only  special  dissections  can  demonstrate, 
have  purposely  been  omitted,  or,  if  introduced,  as  has 
been  done  almost  of  necessity  in  a  few  places,  are  ac- 
companied by  the  statement  that  their  verification  in 
an  ordinary  dissection  is  not  to  be  expected. 

The  order  observed  in  the  following  pages  is  an 
entirely  arbitrary  one,  but  which  an  experience  of 
seven  years  in  demonstrating,  and  more  than  ten  in  the 
special  study  of  Anatomy,  has  shown  to  be  the  most 
convenient  in  the  Dissecting  Room,  and  the  most 
economical  of  material.  The  division  of  the  descrip- 

1* 


VI  PREFACE. 

tions  into  "  dissections,"  each  intended  to  comprise  a 
day's  work,"  it  is  believed  will  be  found  advantageous, 
not  only  as  mapping  out  the  labor  before  the  Dissector, 
but  in  giving  him  an  opportunity  to  prepare  in  the 
study,  and  in  advance,  for  the  dissection  of  each  suc- 
ceeding day.  Practical  suggestions  as  to  the  best 
method  of  demonstrating,  precede  the  descriptions  of 
the  various  regions  and  parts  of  regions.  Illustrations 
have  been  omitted,  for  the  reason  that  they  add  to  the 
expense  of  a  book,  often  without  enhancing  its  real 
value,  and  from  the  belief  that  they  are  liable  to  great 
abuse,  by  distracting  attention  from  the  descriptive  text 
to  the  numbered  references,  the  simple  verification  of 
the  latter  taking  the  place  of  the  full  information  only 
to  be  obtained  from  the  former. 

BOSTON,  Nov.  1858. 


CONTENTS. 

General  Rules  to  be  observed  in  Dissecting  .         .         .  xi 

PART  FIRST. 

ANATOMY    OP   THE    HEAD    AND    NECK. 

DISSECTION  PAGE 

I.  External  Ear 13 

Frontal  and  Orbital  Region       .         .         .         .         .         .15 

II.  Facial  Region 19 

Facial  Arteries          .         .        • 22 

Facial  Nerves 23 

Parotid  Gland  and  Region 24 

III.  Dura  Mater  and  Sinuses .26 

Arteries  and  Muscles  of  the  Orbit     .....       31 

IV.  Cranial  Nerves  at  their  Exit  from  the  Skull      ...       33 
V.  Superficial  Cervical  Region       .         .         .         .         .         .38 

VI.  External  Carotid  Artery 44 

Submaxillary  Region        .......       46 

VII.  Pterygo-maxillary  Region         .         .         .         .  .48 

Articulation  of  the  Lower  Jaw  .....       48 

Deep  Cervical  Region        .         .         .         .         .         .         .51 

VIII.  Sterno-clavicular  Articulation  .....       54 

Base  of  the  Neck 55 

IX.  Pharynx 60 

Palatine  Region  ........  62 

Otic  and  Meckel's  Ganglia 64 

Nasal  Fossae .65 

X.  Tongue 66 

Larynx 68 

XI.  Pre vertebral  Region 72 

Ligaments  of  the  first  two  Vertebrae  .  .  .  .74 
XII.  Anatomy  of  the  Eye 75 


Viii  CONTENTS. 

DISSECTION  PAGE 

XIII.  Membranes  and  Vessels  of  the  Eucephaloii      ...       79 
Origins  of  the  Cranial  Nerves  .         .         .         .         .82 

Medulla  Oblongata  and  Pons  Varolii         .         .  .83 

Base  of  the  Cerebrum      .......       85 

Upper  surface  and  Interior  of  the  Cerebrum    ...       86 
Cerebellum 92 

XIV.  The  Internal  Auditory  Apparatus 94 

Middle  Ear .       95 

Internal  Ear    .         .         . 97 

PART  SECOND. 

ANATOMY  OP  THE  UPPER  EXTREMITY,  THORAX,  AND  BACK. 

I.  Pectoral  and  Deltoid  Region 100 

Axilla 102 

II.  Front  of  the  Arm 105 

Bend  of  the  Elbow .         .109 

III.  Sternal  Region 110 

Ligaments  of  the  Sternum  and  Costal  Cartilages      .         .111 
Anterior  Mediastinum      .         .         .         .         .         .         .112 

Heart 115 

IV.  Posterior  Mediastinum -  120 

Lungs 124 

V.  The  Back  and  Posterior  Cervical  Region  ....  125 

Spinal  Cord  and  Membranes     ......  134 

VI.  Scapular  Region       .         . 137 

Back  of  the  Arm 139 

VII.  Front  of  the  Forearm       . 140 

VIII.  Back  of  the  Forearm  and  Hand 146 

IX.  Palm  of  the  Hand 150 

X.  Ligaments  of  the  Ribs,  Spine,  and  Upper  Extremity         .  156 

PART  THIRD. 

ANATOMY  OP  THE  ABDOMEN  AND  LOWER  EXTREMITY. 

I.  Parietes  of  the  Abdomen 162 

Anatomy  of  Inguinal  Hernia  .         .         .         .         .         .168 

II.  Visceral  Cavity 172 

Peritoneum 173 

Ducts,  Vessels,  and  Nerves  of  the  Abdominal  Cavity       .     176 


CONTENTS.  IX 

DISSECTION  PAGE 

III.  Intestinal  tube 183 

Spleen .     186 

Panoreas  .         . 187 

Liver 187 

IV.  Supra-renal  Capsules 191 

Kidneys  .         .         . .191 

Diaphragm 193 

Superficial  Femoral  Region       ......     195 

Anatomy  of  Femoral  Hernia    ......     196 

Lumbar  Plexus         .         .         .         :         .         .         .         .199 

V.  Anatomy  of  the  Perineum        ......     201 

VI.  Interior  of  the  Pelvis 206 

VII.  Rectum 212 

Bladder 213 

Vesiculse  Seminales  and  Prostate 214 

Penis 215 

Testes 217 

Female  Organs  of  Generation 219 

VIII.  Anterior  Femoral  Region 223 

IX.  Gluteal  Region          .         .         .         .         .         .         .         .229 

X.  Posterior  Femoral  Region          .         .         .         ...         .233 

Popliteal  Space 235 

XI.  Front  of  the  Leg  and  Dorsnm  of  the  Foot         .         .         .237 
XII.  Back  of  the  Leg  .         , 241 

XIII.  Sole  of  the  Foot 245 

XIV.  Ligaments  of  the  Pelvis  and  Lower  Extremity          .         .     249 


Peculiarities  in  the  Anatomy  of  the  Foetus         ....     256 
Important  Anatomical  Landmarks  and  Points,  capable  of  being 

studied  without  dissection,  or  upon  the  living  subject     .     260 


A  FEW  GENEEAL  EULES 


OBSERVED  IN  DISSECTING. 

THE  necessary  incisions  to  expose  any  part,  while  they 
follow  as  nearly  as  may  be  the  direction  of,  and  penetrate 
through  to,  the  muscular  fibres  underlying  them,  should  be 
arranged  in  such  a  manner  as  to  preserve  the  skin  in  the 
largest  possible  flaps,  no  other  covering  of  the  dissection, 
when  temporarily  abandoned,  preserving  it  in  an  equally 
good  condition.  The  skin  is  to  be  removed  only  so  far  as 
freedom  of  dissection,  in  any  given  region,  requires.  The 
fingers  should  take  the  place  of  the  forceps  as  soon  as  the 
skin  is  sufficiently  raised,  as  they  stretch  it  more  evenly 
and  over  a  greater  extent  of  surface. 

In  dissecting  muscles,  the  fibres  must  always,  if  possible, 
be  made  tense.  The  sheath  of  a  muscle  should,  as  a  rule, 
be  detached  with  the  skin  and  never  be  left  behind  for 
subsequent  removal.  The  knife  should  operate  in  long 
sweeps,  using  its  convexity  and  not  its  point,  following 
the  direction  of  the  fibres,  the  dissection  of  any  one 
bundle  of  which  should  be  completed  in  its  whole  length 
before  a  second  is  commenced.  The  forceps  must  never 
seize  the  muscular  fibres,  as  by  so  doing  they  are  torn 
and  made  to  present  a  ragged  appearance.  The  deep 
surface  of  a  muscle  is  to  be  cleaned  as  thoroughly  as 
its  superficial ;  the  tendinous  extremities  are  to  be  isolated 
with  special  pains  that  their  points  of  attachment  may 
be  precisely  studied..  When  muscles  are  to  be  divided, 
the  section  should  always,  if  practicable,  be  made  in  their 


Xll  GENERAL     RULES. 

central  portion,  and  never  at  one  of  their  attachments  ;  the 
two  ends  may  then  at  any  time  be  reapplied,  and  the  deep 
relations,  especially  to  articulations,  can  thus  be  better 
appreciated. 

Arteries  should  be  dissected  with  a  pointed  knife,  and, 
so  far  as  is  practicable,  from  the  trunk  toward  the  branches, 
and  the  branches  from  their  origin  toward  their  termina- 
tion. The  forceps  should  steady  the  artery  by  seizing  its 
sheath,  and  not  the  vessel  itself;  if  the  forceps  are  what 
they  should  be,  this  rule  need  never  be  violated ;  inferior 
forceps  are  a  greater  hinderance  to  neat  dissecting  than 
dull  scalpels.  Nerves  are  to  be  put  upon  the  stretch  with 
hooks,  and  stripped  of  their  cellular  sheath  with  care,  for 
they  are  liable  to  be  unintentionally  divided. 

The  whole  subject,  when  not  in  use,  should  be  covered, 
and  each  part,  with  the  integument  belonging  to  it  replaced, 
should  be  wrapped  around  by  a  bandage  dampened,  not 
wet,  with  water.  Parts  intended  to  be  preserved  for  the 
study  of  the  ligaments  must  be  kept  merely  moist  enough 
to  prevent  drying;  anything  like  maceration  giving  all 
the  tissues  a  uniform  opacity  wrhich  renders  the  distinction 
of  the  ligaments  at  once  difficult  and  unsatisfactory. 

Slowness,  without  unnecessary  delay,  and  industrious, 
systematic  application,  completing  whatever  is  commenced, 
before  beginning  elsewhere,  are  requisites  for  good  dissect- 
ing. Neatness  and  cleanliness,  both  as  to  the  table  and 
the  part  being  dissected,  as  well  as  the  hands  of  the  dis- 
sector, will  contribute,  not  only  to  personal  comfort,  but  to 
the  avoidance  of  diarrhoaa  and  the  dangers  which  some- 
times follow  dissecting  wounds. 

If  a  wound  is  received  while  dissecting,  it  should  imme- 
diately be  held  beneath  the  running  water-faucet  and 
thoroughly  washed  ;  the  bleeding  must  be  encouraged,  and 
any  matter  introduced  drawn  out  by  sucking  the  part.  It 
is  a  questionable  practice  to  cauterize  such  wounds,  but  if 
it  be  done,  a  saturated  solution  is  the  only  form  in  which 
nitrate  of  silver  should  be  used. 


PAET    FIEST. 

ANATOMY  OF  THE  HEAD  AND  NECK. 


THE  dissection  of  the  regions  included  under  the  general  term  of 
"  the  head"  is  considered  the  most  difficult  of  any  in  the  body. 
Comprising  more  important  structures  within  smaller  limits  than 
any  other  part,  and  the  osseous  structure  of  the  skull  constituting 
a  large  portion  of -their  bulk,  it  presents  mechanical  obstacles  not 
easily  surmounted.  It  is  hardly  possible  to  obtain  an  idea  of  all  the 
different  component  parts  in  one  dissection,  as  can  be  done  in  other 
regions  of  the  body ;  the  muscles  and  arteries  may  be  dissected  upon 
one  side  of  the  head,  and  the  other  reserved  for  the  nerves  ;  a  special 
part  is,  however,  desirable  for  the  preparation  of  the  nerves  ;  it  should 
not  be  injected,  and  it  is  well  to  preserve  it  in  spirit,  so  slowly  is 
their  dissection  accomplished. 


DISSECTION  I. 

EXTERNAL    EAR. 

The  dissection  of  the  head  is  usually  commenced  by  an  examination 
of  the  muscles  of  the  ear  ;  for  this  purpose  the  head  rests  upon  its  side, 
and  the  hair  should  be  shaved  from  the  scalp.  A  hook  inserted  into 
and  drawing  the  margin  of  the  ear  successively,  backward  to  dissect  the 
attrahens,  downward  to  dissect  the  attollens,  and  forward  to  dissect 
the  retrahens,  brings  in  turn  the  tendons  of  the  three  auricular  mus- 
cles into  relief;  the  skin  over  these,  with  the  cellular  tissue  beneath, 
being  cautiously  removed,  the  delicate  muscular  fibres,  of  which 
they  are  composed,  may  be  demonstrated.  The  dissection  is  some- 
times made  puzzling  to  the  beginner  by  the  pale  color  and  small  size 
of  the  aural  muscles. 

The  muscles  which  attach  the  ear  to  the  side  of  the  head 
are  called  its  extrinsic  muscles,  and  are  three  in  number ; 
the  special  muscles  of  its  cartilage,  or  pinna,  are  called 
intrinsic. 

The  ATTRAHENS  AUREM  is  the  most  anterior  of  the  ex- 
trinsic muscles ;  it  arises,  pale  and  indistinct,  from  the 
epicranial  aponeurosis,  just  above  the  zygoma,  and  its 
fibres  are  directed  backward  to  be  inserted  into  the  anterior 
2 


14  ANATOMY    OF    THE    HEAD    AND    NECK. 

part  of  the  cartilaginous  rim  of  the  ear.  It  is  often  want- 
ing, or  its  place  is  supplied  by  the  anterior  fibres  of  the 
attollens  aurem. 

The  ATTOLLENS  AUREM  is  a  better-marked  muscle  than  the 
preceding;  it  arises,  fan-shaped,  from  the  epicranial  aponeu- 
rosis,  on  the  side  of  the  head  above  the  ear,  and  is  inserted 
into  the  upper  and  anterior  part  of  the  concha  of  the  ear. 

The  RETRAHENS  AUREM  arises  by  several  separate  slips 
from  the  mastoid  process  of  the  temporal  bone,  and  is 
inserted  into  the  posterior  surface  of  the  concha.  This  is 
usually  the  largest  and  best  marked  of  the  aural  muscles. 

In  dissecting  these  muscles  the  anterior  auricular  artery, 
a  branch  of  the  temporal,  and  the  posterior  auricular,  a 
branch  of  the  external  carotid,  or  sometimes  of  the  occipi- 
tal, will  be  seen ;  they  are  distributed  as  their  names  indi- 
cate. 

The  following  nerves  should  also  be  sought  for  in  this 
connection.  The  auricularis  magnus  nerve,  an  ascending 
branch  of  the  anterior  cervical  plexus,  is  distributed  to 
the  back  of  the  ear  j  the  posterior  auricular,  a  branch  of 
the  facial  nerve,  accompanies  the  artery  of  the  same  name, 
and  is  distributed  to  the  ear  and  occipital  region.  The 
occipitalis  major,  a  posterior  branch  of  the  second  cervical 
nerve,  emerging  from  the  deep  muscles  of  the  back  of  the 
neck,  and  accompanying  in  part  of  its  course  the  occipital 
artery,  sends  a  branch  to  the  ear.  The  occipitalis  minor 
nerve,  another  ascending  branch  of  the  anterior  cervical 
plexus,  is  placed  midway  between  the  last  named  and  the 
posterior  auricular,  with  both  of  which  it  communicates ; 
it  supplies  the  attollens  aurem  muscle  and  the  integument. 

The  EXTERNAL  EAR  is  described  as  consisting  of  the 
pinna  or  auricle,  and  the  meatus.  The  pinna,  or  projecting 
part  of  the  ear,  consists  of  a  number  of  folds  and  hollows, 
which  have  been  named  as  follows :  the  external  folded 
margin  is  called  the  helix  ;  the  elevation  which  runs  parallel 
to  it,  the  anti-helix;  the  process  projecting  over  the  meatus 
is  the  tragus;  opposite  to  this  is  a  prominence  called  the 
anti-tragus  ;  the  dependent  portion  of  the  ear  is  called  the 
lobule;  the  central  depression  around  the  meatus  is  the 
concha;  the  space  between  the  helix  and  the  anti-helix, 
the  fossa  innominata;  this  terminates  anteriorly  in  a 
triangular  depression  called  the  scaphoid  fossa.  The 
meatus  is  the  cartilaginous  canal  leading  from  the  pinna 
to  the  tympanum,  a  thin,  transparent  membrane  at  the 


FRONTAL    AND     ORBITAL    REGION.  15 

bottom  of  this  canal,  which  separates  the  external  from 
the  middle  ear. 

The  muscles  of  the  pinna  require  a  patient  dissection  ;  indeed,  they 
are  not  always  to  be  found,  being  only  rudimentary  in  man.  The 
integument  covering  them  is  very  thin  and  delicate. 

The  intrinsic  muscles  of  the  ear  are  five  in  number. 

The  major  helicis  consists  of  vertical  fibres,  to  be  found 
on  the  anterior  border  of  the  helix,  just  above  the  tragus. 

The  minor  helicis  is  placed  upon  that  part  of  the  helix 
which  extends  into  the  concha;  its  fibres  are  arranged 
obliquely. 

The  tragicus  is  a  vertical  bundle  of  fibres  situated  on  the 
outer  surface  of  the  tragus. 

The  anti-tragicus  arises  from  the  outer  part  of  the  anti- 
tragus,  and  its  fibres  converge  to  be  inserted  into  the 
pointed  extremity  of  the  anti-helix. 

The  transversus  auriculae  is  found  on  the  posterior  aspect 
of  the  ear,  stretching  transversely  across  the  depression 
between  the  helix  and  the  concha. 

On  removing  all  the  integument,  the  pinna  of  the  ear 
will  be  found  to  consist  of  a  single  cartilage,  presenting 
the  general  outlines  of  the  ear  ;  it  does  not  extend  into  the 
lobule,  and  its  continuity  is  broken  by  notches  and  fissures. 
It  is  firmly  attached  to  the  processus  auditorius  of  the 
temporal  bone  by  a  cartilaginous  tube  called  the  vneatus 
auditorius  externus.  In  the  subcutaneous  cellular  tissue  of 
the  meatus  are  the  ceruminous  glands,  which  secrete  the 
wax  of  the  ear. 

FRONTAL  AND  ORBITAL  REGION. 

To  dissect  the  occipito-frontalis  muscle,  make  an  incision  from  the 
root  of  the  nose  backward  to  the  occiput ;  this  should  be  met  at  the 
vertex  by  an  incision  made  from  the  ear  at  right  angles  to  it ;  another 
must  be  carried  along  the  eyebrow,  from  the  root  of  the  nos-e  outward. 
The  flap  is  to  be  lifted  from  the  nasal  angle,  and  with  great  care  ;  for  the 
fibres  are  traced  with  difficulty,  and  the  thin  plane  which  they  con- 
stitute is  very  adherent  to  the  integument  and  liable  to  be  cut  through 
or  dissected  up  from  the  bone  upon  which  it  lies ;  the  aponeurotic 
tendon  which  expands  over  the  vertex  of  the  skull  can  hardly  fail 
of  being  disfigured  by  "  button-holes." 

The  OCCIPITO-FRONTALIS  MUSCLE  consists  of  two  portions, 
a  frontal  and  an  occipital ;  the  two  being  connected  b}'  an 
iiponeurosis,  which  expands  over  the  vertex  of  the  cranium. 
It  may  therefore  be  described  as  arising  from  the  external 


16  ANATOMY    OF    THE     HEAD    AND     NECK. 

part  of  the  superior  curved  line  of  the  occipital  bone,  and 
from  the  mastoid  portion  of  the  temporal  bone  to  form  a 
rounded  and  flat  belly,  which  terminating  in  an  aponeu- 
rosis,  passes  forward  to  join  the  frontal  portion  lying  upon 
the  frontal  bone;  this,  broader  and  thinner  than  the 
occipital,  confounds  itself  with  the  orbicularis  palpebra- 
rum,  pyramidalis  nasi  and  corrugator  supercilii  muscles, 
and  is  inserted  into  the  nasal  bones  and  the  superciliary 
ridge  of  the  frontal  bone.  Anteriorly  the  muscular  bellies 
of  the  two  sides  blend  together ;  posteriorly  they  are  sepa- 
rated by  an  interval  completed  by  an  aponeurotic  expan- 
sion. 

It  might  seem  better,  perhaps,  to  describe  the  occipito- 
frontalis  as  two  muscles  instead  of  one  single  digastric 
muscle ;  each  being  inserted  into  the  epicranial  aponeurosis. 
This  would  be  suggested  by  its  action,  it  being  a  muscle  of 
expression,  and  is  the  manner  in  which  it  is  described  by 
some  authors.  The  aponeurosis  connecting  the  two  por- 
tions of  the  occipito-frontalis  is  firmly  connected  with  the 
skin,  though  but  loosely  attached  to  the  pericranium.  It 
expands  over  the  vertex  without  any  separation  into  lateral 
parts,  and  upon  the  sides  of  the  head  is  thin  and  amounts 
to  little  more  than  cellular  tissue. 

Upon  the  posterior  belly  of  the  occipito-frontalis  muscle 
will  be  found  the  occipitalis  major  nerve,  a  posterior  branch 
of  the  second  cervical  nerve,  and  the  occipital  artery,  a 
branch  of  the  external  carotid.  The  artery  is  tortuous,  and 
supplies  the  muscle,  integument,  and  epicranium  ;  it  anasto- 
moses with  the  temporal  artery,  and  sometimes  gives  off  the 
posterior  auricular  branch  to  the  external  ear.  The  nerve 
accompanies  the  artery  only  in  a  part  of  its  course,  and  is 
distributed  chiefly  to  the  integument. 

The  PYRAMIDALIS  NASI  is  a  slip  of  the  occipito-frontalis 
passing  downward  upon  the  bridge  of  the  nose.  Its  out- 
line is  usually  confused,  and  it  is  inserted  into  the  nasal 
bone  and  the  compressor  muscle  of  the  nose.  Properly,  it 
should  be  considered  as  a  pillar  of  origin  of  the  frontal 
belly  of  the  occipito-frontalis. 

The  ORBICULARIS  PALPEBRARUM  surrounds  the  eye,  and 
is  seen  by  dissecting  the  integument  from  the  eyelids,  upon 
which  it  expands,  as  it  also  does  upon  the  circumference  of 
the  orbit ;  it  is  a  thin  muscular  plane,  difficult  to  dissect, 
owing  in  a  degree  to  the  want  of  fixedness  in  the  parts  upon 
which  it  rests.  Its  fibres  are  well  marked,  and  it  arises  from 


FRONTAL    AND    ORBITAL    REGION.  1*7 

the  inner  angle  of  the  frontal  bone,  the  nasal  process  of  the 
superior  maxillary,  and  the  tendon  of  the  tarsal  cartilages ; 
encircling  the  orbit,  it  is  inserted  into  the  same  point  from 
which  it  arose,  thus  making  a  sphincter  muscle.  At  the 
inner  angle  of  the  orbit  certain  ascending  fibres  of  the 
orbicularis,  springing  from  the  tendon  of  the  tarsal  carti- 
lages, expand  fan-shaped,  are  inserted  into  the  inner  half 
of  the  eyebrow,  and  have  received  the  name  of  depressor 
supercilii. 

The  CORRUGATOR  SUPERCILII  lies  beneath  the  upper  half 
of  the  orbicularis  palpebrarum,  which  must  be  dissected  up 
in  order  to  expose  it.  It  is  usually  confounded  with  the 
orbicularis,  and  not  always  to  be  satisfactorily  separated 
from'  it.  It  arises  from  the  inner  part  of  the  superciliary 
ridge,  and  is  inserted  into  the  under  surface  of  the  orbicu- 
laris and  frontalis  muscles,  being  about  an  inch  in  length. 
Upon  the  frontal  bone,  beneath  the  muscles  last  dissected, 
will  be  found  the  divisions  of  the  supra-orbital  nerve,  a 
branch  of  the  fifth  cranial  pair;  these  emerge  from  the 
supra-orbital  notch,  and  after  supplying  the  muscles  which 
lie  over  it,  are  distributed  to  the  epicranium  and  integu- 
ment of  the  forehead.  This  nerve  is  accompanied  by  the 
supra-orbital  branch  of  the  ophthalmic  artery,  a  branch 
of  the  internal  carotid  ;  emerging  at  the  supra-orbital  fora- 
men, it  divides  and  is  distributed  like  the  nerve. 

The  EYELIDS  consist  of  two  cartilages,  one  for  the  upper 
and  one  for  the  lower  lid,  that  of  the  upper  being  the 
largest ;  they  are  covered  externally  by  muscles  and  integu- 
ment, and  along  their  free  border  the  eyelashes  are  inserted  ; 
both  are  semi-lunar  in  shape,  and  attached  to  the  edge  of 
the  orbit  by  a  membrane  called  the  ligamentum  palpebrse. 
A  small  fibrous  band,  called  the  tendo  oculi,  arising  from  the 
anterior  margin  of  the  lachrymal  canal  and  dividing  into 
processes,  one  for  each  cartilage,  fixes  them  internally ;  a 
fibrous  band  also  attaches  them  to  the  margin  of  the  orbit 
externally.  They  are  invested  internally  by  a  mucous  mem- 
brane called  the  conjunctiva ;  this  is  continuous  with  that 
covering  the  eyeball,  from  which  it  is  reflected,  and  on  both 
surfaces  is  movable  and  vascular ;  over  the  cornea  it  is  thin 
and  transparent,  and  in  the  state  of  health  no  vessels  are 
traceable  in  that  part.  On  the  ocular  surface  of  the  carti- 
lages may  be  seen  numerous  parallel  and  somewhat  tortu- 
ous lines,  indicating  the  Meibomian  glands,  which  open 
along  the  free  edges  of  the  eyelids.  The  lachrymal  canal 

2* 


18      ANATOMY  OF  THE  HEAD  AND  NEC  1C. 

has  an  opening  at  the  inner  extremity  of  each  eyelid,  indi- 
cated by  a  slight  prominence,  in  the  centre  of  which  is  a 
small  orifice  called  the  punctum  lacrymale.  The  canals  of 
the  two  lids  uniting  form  a  common  canal,  less  than  one- 
eighth  of  an  inch  in  length,  terminating  in  the  lachrymal 
'sac,  which  occupies  the  concave  portion  of  the  lachrymal 
bone.  This  sac  is  the  expanded  upper  part  of  the  nasal 
duct,  which  conve37s  the  tears  from  the  lachrymal  canals  to 
the  inferior  meatus  of  the  nasal  fossa  (p.  65).  In  the  inter- 
nal commissure  of  the  eyelids  there  is  a  prominent  reddish 
body  formed  from  the  conjunctiva,  and  called  the  carun- 
cula  lacrymalis  ;  just  external  to  this  is  a  fold  of  the  con- 
junctiva, called  plica  semilunaris,  in  which  may  sometimes 
be  found  a  minute  cartilage ;  this  is  considered  as  corres- 
ponding to  the  third  lid  or  membrana  nictitans  of  birds. 

The  eyelids  are  supplied  by  the  palpebral  arteries, 
branches  of  the  ophthalmic,  given  off  near  the  inner  angle 
of  the  orbit;  the  nasal,  another  branch  from  the  same 
source,  emerges  above  the  tendo  oculi,  and  inosculates  with 
the  angular  branch  of  the  facial  artery;  the  frontal,  also 
from  the  ophthalmic,  appears  near  the  same  point,  and  is 
distributed  to  the  forehead. 

The  LACHRYMAL  GLAND  is  situated  in  the  hollow  of  the 
external  angular  process  of  the  frontal  bone,  and  admits 
of  examination  at  this  time  by  dividing  the  upper  e3Telid 
at  its  centre  and  at  its  external  angled  It  is  a  thin  flat- 
tened body,  the  size  of  a  small  chestnut,  resembling  in  its 
structure  the  salivary  glands  ;  it  sends  a  prolongation  down 
upon  the  cartilage  of  the  upper  eyelid,  but  its  principal 
portion  lies  in  contact  with  tlje  periosteum,  to  which  it  is 
held  by  a  few  fibrous  bands ;  its  inferior  surface  rests  upon 
the  eyeball  and  the  external  rectus  muscle.  It  receives  a 
branch  of  the  ophthalmic  arter}-. 

To  see  Homer's  muscle,  the  eyelids  must  be  divided  in  the  middle 
l>y  a  transverse  cut  and  turned  toward  the  nose  ;  the  conjunctiva,  with 
the  fat  and  cellular  tissue  tilling  the  inner  angle  of  the  eye,  must  be 
dissected  awny. 

The  TENSOR  TARSI,  or  HORNER'S  MUSCLE,  consists  of  a 
quadrilateral  plane  of  delicate  fibres,  closely  applied  to  and 
arising  from  the  lachrymal  bone ;  it  is  about  four  lines  wide 
and  six  lines  long  ;  anteriorly  it  splits  into  two  bands, 
which  terminate  in  very  delicate  tendons,  to  be  inserted 
into  each  tarsal  cartilage  by  the  side  of  its  lachrymal  duct. 


FACIAL    REGION.  19 

DISSECTION  II. 

FACIAL   REGION. 

In  order  to  dissect  the  muscles  of  the  face,  the  lips  and  cheeks 
should  be  distended  by  filling  the  space  between  them  and  the  teeth 
with  cotton  wool  or  like  material  ;  the  lips  are  then  to  be  sewed 
together;  the  nostrils  may  be  distended  in  the  same  manner.  One 
side  should  be  dissected  at  a  time,  the  other  being  preserved  to 
verify  the  first :  for  the  very  feeble  development  of  the  facial  muscles 
makes  it  difficult  to  distinguish  them  ;  the  class  of  individuals  who 
finish  their  career  in  the  dissecting-room,  is  not  calculated  to  display 
the  muscles  of  expression  about  the  nose  and  mouth,  as  it  does  those 
of  the  arms  or  legs  developed  by  constant  use. 

The  integument  should  be  turned  downward  from  the  inner  side  of 
the  orbit ;  and  as  the  inferior  segment  of  the  orbicularis  palpebrarum 
muscle  covers  in  the  origin  of  several  facial  muscles,  it  should  be 
dissected  up  so  as  to  expose  them. 

The  LEVATOR  LABII  SUPERIORIS  AL^QUE  NASI  occupies 
the  depression  at  the  side  of  the  nose ;  it  arises  from  the 
nasal  process  of  the  superior  maxillary  bone,  beneath  the 
orbicularis  palpebrarum,  and  expanding  as  it  descends,  is 
attached  to  the  ala  of  the  nose  and  the  surface  of  the  upper 
lip,  where  it  becomes  confounded  with  the  orbicularis  oris. 
The  fibres  attached  to  the  ala  of  the  nose  are  often  but  a 
small  part  of  the  whole  number,  and  few  and  faint  in 
appearance. 

The  LEVATOR  LABII  SUPERIORIS  PROPRIUS  is  a  quadri- 
lateral muscle,  covered  in  by  a  considerable  amount  of 
adipose  tissue,  and  partially  obscured  by  the  preceding 
muscle  and  the  orbicularis  palpebrarum ;  it  is  a  very  dis- 
tinctly characterized  muscle,  arising  from  the  lower  edge 
of  the  orbit  and  the  surface  of  bone  beneath,  and  is 
inserted  into  the  integument  of  the  upper  lip  by  fibres 
which  become  confounded  with  the  orbicularis  oris. 

Beneath  this  muscle  will  be  found  the  branches  of  the 
infra-orbital  nerve ;  being  the  terminal  filaments  of  the 
superior  maxillary  branch  of  the  fifth  pair  of  cranial 
nerves  ;  they  emerge  at  the  infra-orbital  foramen,  and,  ex- 
panding on  the  side  of  the  nose  and  upper  lip,  freely 
anastomose  with  branches  of  the  facial  nerve.  This 
nerve  is  accompanied  by  the  infra-orbital  vein,  and  by  the 
terminal  branches  of  the  internal  maxillary  artery,  called 
the  infra-orbital;  these  emerge  also  at  the  infra-orbital 


20  ANATOMY    OF    THE    HEAD    AND     NECK. 

foramen,  and  are  distributed  like  the  accompanying  nerve, 
anastomosing  with  branches  of  the  facial  artery. 

The  ZYGOMATICUS  MINOR  MUSCLE  is  the  internal  of  two 
slender  muscular  slips  passing  from  the  malar  bone  to  the 
angle  of  the  mouth ;  it  arises  from  the  face  of  the  malar 
bone  and  passes  obliquely  to  the  integument  of  the  lip 
near  its  angle,  where  it  is  inserted,  blending  with  the  in- 
sertion of  the  levator  labii  superioris  proprius.  This  mus- 
cle is  very  often  wanting, — and,  when  present,  seems  to  be 
a  bundle  of  fibres  of  the  orbicularis  palpebrse  detached,  to 
pass  downward  to  the  angle  of  the  lips. 

The  ZYGOMATICUS  MAJOR  MUSCLE  arises  outside  the  pre- 
ceding, from  the  surface  of  the  malar  bone  near  its  external 
angle,  and  is  inserted  into  the  integument  of  the  angle  of 
the  lips,  blending  with  the  orbicularis  oris.  As  its  name 
implies,  this  muscle  is  considerably  larger  than  its  com- 
panion. 

The  LEVATOR  ANGULI  ORIS  arises  from  the  canine  fossa 
of  the  superior  maxillary  bone,  and  is  covered  in  by  the 
levator  labii  superioris  proprius,;  it  is  inserted  into  the 
angle  of  the  mouth,  where  it  confounds  itself  with  the 
orbicularis  oris  and  the  other  muscles  converging  at  that 
point. 

The  DEPRESSOR  LABII  SUPERIORIS  AL^QUE  NASI  can 
only  be  seen  by  turning  the  upper  lip  inside  out  and 
dissecting  off  the  mucous  membrane  on  each  side  of  the 
frenum ;  it  is  a  small,  pale  muscle,  not  easily  detected,  the 
fibres  of  which  are  confounded  with  those  of  the  orbicularis 
oris  ;  it  arises  from  the  fossa  in  the  superior  maxillary  bone 
just  above  the  incisor  teeth,  and  is  inserted  into  the  upper 
lip  and  the  cartilages  of  the  ala  and  septum  of  the  nose. 

The  COMPRESSOR  NASI  expands  in  a  radiated  manner 
upon  the  side  of  the  nose ;  its  fibres  are  very  thin  and  pale, 
and  its  origin  is  covered  in  by  the  levator  labii  superioris 
proprius ;  it  arises  from  the  canine  fossa  of  the  superior 
maxillary  bone,  and  ends  in  an  aponeurosis  covering  the 
cartilaginous  part  of  the  nose,  joining  the  tendon  of  the 
other  side :  its  precise  limits  are  difficult  to  establish. 

The  CARTILAGES  OF  THE  NOSE  are  five  in  number,  two 
on  each  side,  and  one  in  the  centre,  the  latter  forming  the 
septum  of  the  nostrils.  The  superior  are  called  the  lateral 
fibro-cartilages ;  they  are  triangular  in  shape,  and  are 
attached  posteriorly  to  the  nasal  bones  and  the  nasal  pro- 
cess of  the  superior  maxillary  bone  ;  anteriorly  they  are 


FACIAL    REGION.  21 

attached  to  the  anterior  border  of  the  septum.  Below 
these  are  the  alar  fibro-cartilages ;  these  are  curved  in 
such  a  way  as  to  form  the  rim  of  the  nostril;  anteriorly 
they  form  the  apex  of  the  nose,  and  their  inner  portions 
at  this  part  turn  backward  along  the  septum  nasi.  This 
cartilage  has  no  osseous  attachment,  but  is  connected  by 
fibrous  tissue  with  th'e  lateral  cartilages  and  the  integu- 
ment. To  the  outer  curve  of  the  alar  cartilage  are  at- 
tached several  small  cartilages  connected  with  each  other 
by  fibrous  tissue ;  these  are  called  the  sesamoid  cartilages. 
The  septum  nasi  is  triangular  in  form  and  divides  the  nose 
into  its  two  nostrils :  it  is  attached  above  to  the  nasal 
bones  and  lateral  cartilages,  posteriorly  it  unites  with  the 
vomer,  and  below  with  the  palate  process  of  the  superior 
maxillary  bones. 

The  ORBICULARIS  ORIS  is  an  elliptical-shaped  muscle 
forming  a  sphincter  round  the  mouth ;  it  has  no  osseous 
attachment;  its  fibres  cross  each  other  at  the  angles  of  the 
mouth ;  those  belonging  to  the  upper  lip  join  the  lower 
portion  of  the  buccinator  muscle,  and  those  from  the  lower 
lip  join  with  the  upper  part  of  the  same  muscle.  Beneath 
this  muscle  lies  the  mucous  membrane  of  the  lips,  and  be- 
tween this  and  the  muscular  fibres  are  the  coronary  branch 
of  the  facial  artery,  and  numerous  small,  rounded  mucous 
glands,  called  labial  glands. 

The  DEPRESSOR  LABII  INFERTORIS,  or  QUADRATUS  MENTT, 
arises  from  the  oblique  line  of  the  inferior  maxillary  bone, 
and,  blending  with  its  fellow  of  the  opposite  side,  is  in- 
serted into  the  orbicularis  oris  at  the  central  part  of  the 
portion  belonging  to  the  lower  lip. 

The  DEPRESSOR  ANGULI  ORIS,  or  TRIANGULARIS  MENTT, 
arises  more  externally  from  the  same  oblique  line  of  the 
inferior  maxillary  bone,  and  is  inserted  into  the  orbicularis 
oris  near  the  angle  of  the  lips ;  its  most  external  fibres  will 
be  found  continuous  with  some  of  those  of  the  zygomaticus 
major. 

Both  of  the  last-described  muscles  are  made  up  of  fibres 
from  the  platysma  myoides  of  the  neck ;  and  if  they  have 
been  carefully  dissected,  the  continuity  may  be  traced  with 
the  greatest  ease. 

Beneath  the  depressor  anguli  oris  will  be  seen  issuing 
from  the  mental  foramen,  the  termination  of  the  inferior 
dental  branch  of  the  inferior  maxillary  trunk  of  the  fifth 
pair  of  cranial  nerves  ;  its  filaments  suppl}r  the  muscles  and 


22  ANATOMY     OF     THE     HEAD    AND     NECK. 

integument  of  the  lower  lip  and  anastomose  with  branches 
of  the  facial  nerve.  The  inferior  dental  branch  of  the 
internal  maxillary  artery,  accompanied  by  its  vein,  also 
emerges  at  the  mental  foramen,  and,  communicating  with 
the  facial  artery,  is  distributed  to  the  structures  covering 
the  lower  jaw. 

The  LEVATOR  LABII  INFERIORIS  is  an  extremely  small 
muscle,  difficult  to  isolate;  it  is  to  be  sought  from  the 
inside  of  the  under  lip,  which  should  be  turned  down  and 
the  frenum  divided.  The  muscle  arises  from  the  surface  of 
bone  just  below  the  incisor  teeth,  and  is  inserted  into  the 
integument  on  the  tip  of  the  chin. 

The  BUCCINATOR  MUSCLE  arises  from  the  outer  surface 
of  the  alveolar  borders  of  the  upper  and  lower  jaw,  as  far 
forward  as  the  first  molar  tooth ;  also  from  a  fibrous  raphe 
called  the  pterygo-maxillary  ligament,  which  intervenes 
between  it  and  the  superior  constrictor  of  the  pharynx ; 
its  fibres  converge  anteriorly  and  become  continuous  with 
those  of  the  orbicularis  oris.  The  intersection  of  the 
muscles  anteriorly  should  be  dissected  with  special  care. 
At  about  its  centre,  the  buccinator  is  perforated  by  the 
excretory  duct  (Steno's)  of  the  parotid  gland ;  this  lies 
partly  imbedded  in  a  quantity  of  fat  which  occupies  the 
interval  between  this  muscle  and  the  masseter,  and  care 
must  therefore  be  taken  not  to  divide  it. 

The  RISORIUS  SANTORINI  MUSCLE  consists  of  a  few  fibres 
of  the  platysma  myoides,  varying  in  their  degree  of  dis- 
tinctness, which  pass  transversely  inward  over  part  of  the 
buccinator  and  masseter  muscle,  to  terminate  near  the 
angle  of  the  mouth. 

FACIAL   ARTERIES. 

The  facial  arteries  may  be  made  the  subject  of  a  special  dissection 
upon  one  side  of  the  face  ;  or,  if  the  student  has  been  careful  to  pre- 
serve them  in  connection  with  the  muscles,  they  may  be  studied  on 
the  side  already  dissected.  The  arteries  proper  of  the  face  are  the 
facial  and  transverse  facial ;  the  former  a  branch  of  the  external 
carotid,  the  latter  of  the  temporal  artery. 

The  FACIAL  ARTERY  emerges  from  the  neck  just  anterior 
to  the  masseter  muscley  where  it  rests  upon  the  lower  jaw, 
covered  in  by  the  platysma  myoides ;  it  passes  upward 
obliquely  and  tortuously :  near  the  angle  of  the  mouth  it 
gives  off  an  inferior  labial  branch,  which  passes  beneath 
the  depressor  anguli  oris  muscle,  and  is  distributed  to  the 


FACIAL    NERVES.  23 

lower  lip  and  chin.  The  superior  and  inferior  coronary 
branches  are  given  off  separately,  or  by  a  common  trunk; 
they  supply  the  upper  and  lower  lip,  lying  "between  the 
orbicularis  oris  muscle  and  the  mucous  membrane,  and 
inosculate  with  the  corresponding  branches  of  the  opposite 
side.  The  superior  coronary  sends  a  branch  to  the  septum 
of  the  nose.  The  facial  continues  up  beside  the  nose  under 
the  name  of  the  lateralis  nasi,  its  termination  being  called 
the  angular  artery,  and  anastomoses  with  the  nasal  branch 
of  the  ophthalmic.  The  facial  artery  is  apt  to  be  irregular, 
and  is  seldom  symmetrical  on  the  two  sides  of  the  face. 

The  facial  vein  accompanies  the  facial  artery  on  its  outer 
side,  and,  uniting  with  the  temporal  vein,  terminates  in  the 
internal  jugular  vein. 

The  TRANSVERSE  FACIAL  ARTERY  is  a  branch  of  the 
temporal  arteiy ;  it  emerges  at  the  anterior  border  of  the 
parotid  gland,  and  lies  beside  the  parotid  duct ;  it  anasto- 
moses with  the  facial  arter}^  and  supplies  the  muscles 
and  integument.  It  occasionally  arises  from  the  external 
carotid. 

FACIAL   NERVES. 

If  a  special  part  is  not  to  be  obtained  for  the  dissection  of  the  facial 
nerves,  they  may  be  examined  on  a  side  of  the  face  reserved  for  that 
purpose,  or,  if  sufficiently  preserved,  in  connection  with  the  dissec- 
tion already  made.  Some  of  the  nerves  are-  concealed  by  the 
parotid  gland,  but  a  greater  part  are  external  to  it ;  the  external 
branches  are  to  be  followed  out  one  by  one,  and,  to  see  those  within 
the  gland,  it  must  be  removed  piece  by  piece  while  tracing  them 
backward. 

The  FACIAL  NERVE  is  a  portion  of  the  seventh  cranial 
nerve,  and  issues  from  the  skull  at  the  stylo-mastoid  fora- 
men ;  it  divides  near  the  ramus  of  the  jaw  into  two 
divisions,  the  temporo-facial  and  the  cervico-facial ;  the 
posterior  auricular  branch,  which  was  dissected  with  the 
external  ear,  is  given  off  close  to  the  skull,  and  turns 
upward  in  front  of  the  mastoid  process  to  supply  the 
attrahens  and  attollens  aurem  and  the  posterior  belly  of 
the  occipito-frontalis  muscle. 

The  temporo-facial  division  gives  off  a  large  number  of 
filaments,  which  expand  upon  the  side  of  the  face  as 
temporal,  malar,  and  infra-orbital  branches,  anastomosing 
freely  with  the  supra-orbital  and  infra-orbital  branches  of 
the  fifth  cranial  nerve. 

The   cervico-facial    division   is    smaller    than    the    pre- 


24  ANATOMY    OF    THE     HEAD    AND     NECK. 

ceding ;  its  filaments  are  distributed  upon  the  lower  part 
of  the  face  as  buccal,  supra-maxillarj-  and  infra-maxillary 
branches ;  the  supra-maxillary  branches  course  inward 
toward  the  chin,  and  beneath  the  depressor  anguli  oris 
anastomose  with  the  inferior  dental  branch  of  the  fifth 
nerve.  The  web-like  aspect  of  this  network  of  communi- 
cating branches  has  given  them  collectively  the  name  of 
pes  anserinus. 

The  auriculo-temporal  branch  of  the  inferior  maxillary 
trunk  of  the  fifth  pair  is  also  partly  seen  in  this  dissec- 
tion ;  it  emerges  from  beneath  the  parotid  gland  and 
ascends  in  company  with  the  temporal  arteiy  to  the  side 
of  the  head;  it  communicates  with  the  facial  nerve  and 
supplies  the  integument  in  front  of  the  ear,  the  terminal 
branches  being  distributed  to  the  epicranial  and  temporal 
aponeuroses. 

The  infra-maxillary  branches  are  situated  below  the 
lower  jaw,  lying  beneath  the  plat3rsma,  and  ramify  as  far 
as  the  hyoid  bone. 

PAROTID   GLAND    AND   REGION. 

The  PAROTID  GLAND,  the  largest  of  the  salivary  glands,  is 
an  irregularly  shaped  body  made  up  of  lobes  and  lobules  ; 
it  lies  in  front  of  the  ear,  and  is  partly  covered  by  the  pla- 
tysma  muscle  ;  it  is  limited  above  by  the  zygomatic  arch, 
behind  by  the  meatus  of  the  ear  and  the  sterno-mastoid 
muscle;  inferiorly,  it  descends  as  low  as  the  posterior 
belly  of  the  digastricus  muscle,  and  its  deep  surface  pene- 
trates in  various  directions  to  a  considerable  depth ; 
anteriorly,  it  expands  upon* the  side  of  the  face,  and  a 
small  accessory  part,  called  soda  parotidis,  is  prolonged 
from  it  over  the  masseter  muscle.  Its  excretory  duct, 
called  the  duct  of  Steno,  is  given  off  from  the  anterior  por- 
tion ;  it  can  be  traced  but  a  short  distance  into  the  sub- 
stance of  the  gland  itself;  the  length  of  the  duct  is  about 
two  inches  and  a  half,  and  its  size  is  about  equal  to  that  of 
a  crow-quill.  It  is  composed  of  a  fibrous  and  a  mucous 
coat,  and  perforates  the  cheek  obliquely  opposite  the 
second  molar  tooth  of  the  upper  jaw.  A  line  drawn 
from  the  meatus  auditorius  to  a  little  below  the  nostril 
would  mark  the  course  of  the  duct  in  the  cheek,  and  its 
orifice  would  correspond  to  a  spot  midway  between  these 
two  limits.  This  is  a  point  to  be  remembered  in  operations 
on  the  face.  The  internal  carotid  arteiy  and  internal  jugu- 


PAROTID    GLAND    AND    REGION.  25 

lar  vein  lie  beneath  the  gland  ;  the  external  carotid,  accom- 
panied by  several  large  veins,  passes  through  its  middle, 
sending  off  numerous  branches ;  curving  from  behind  for- 
ward the  facial  nerve  divides  within  its  substance.  Its 
own  vessels  and  nerves  are  derived  from  the  external 
carotid  artery  and  the  facial  nerve. 

The  examination  of  the  parotid  will  demonstrate  the  danger,  if 
not  the  impossibility,  of  completely  extirpating  this  body  during 
life  ;  even  in  the  dead  subject  it  will  be  found  that  it  is  a  very  nice 
dissection  to  remove  it  neatly  and  properly.  The  scissors  will  be 
found  a  useful  instrument  in  this  operation,  which  should  be  com- 
menced from  the  external  carotid  ;  the  branches  of  this,  many  of 
which  are  small,  should  all  be  saved,  so  that  when  the  gland  is 
removed  the  artery  shall  be  left  with  all  its  offsets. 

The  MASSETER  MUSCLE  arises  from  both  surfaces  of  the 
zygoma  and  from  the  malar  bone,  and  is  inserted  into  the 
outer  surface  of  the  coronoid  process,  ramus,  and  angle  of 
the  inferior  maxillar}^  bone.  In  shape  it  is  quadrilateral; 
externally  it  is  covered  by  a  strong  shining  aponeurosis 
obscuring  its  muscular  fibres,  and  which  is  not  to  be 
removed.  The  direction  of  the  superficial  fibres  of  this 
muscle  is  obliquely  backward ;  of  its  deeper  fibres  obliquely 
forward. 

The  TEMPORAL  APONEUROSIS  is  a  brilliant  fibrous  mem- 
brane covering  in,  and  at  its  upper  part  adherent  to,  the 
temporal  muscle :  it  is  attached  superiorly  to  the  curved 
line  that  limits  the  temporal  fossa,  and  below  to  the 
Z3'goma  by  two  layers,  between  which  there  is  a  layer 
of  loose  fat  and  cellular  tissue. 

The  TEMPORAL  ARTERY  ramifies  upon  the  temporal 
aponeurosis  ;  it  is  one  of  the  terminal  branches  of  the 
external  carotid,  arising  within  the  parotid  gland,  where 
it  gives  off  the  transverse  facial  branch  (p.  23).  Ascending 
upon  the  temporal  fascia,  just  above  the  zygoma,  it  sends  a 
small  branch,  called  the  middle  temporal,  through  the  fascia 
to  the  temporal  muscle,  and  then  divides  into  two  branches, 
anterior  and  posterior  ;  the  anterior  is  distributed  in  a  very 
tortuous  manner  to  the  forehead,  where  it  anastomoses  with 
the  supra-orbital  branch  of  the  ophthalmic  artery;  the  pos- 
terior passes  backward  to  the  occiput,  where  it  anastomoses 
with  the  occipital  artery. 

The  temporal  aponeurosis  is  to  be  incised  around  its  edges  and  re- 
moved ;  the  zygoma  is  to  be  cut  through  with  a  chisel  just  in  front  of 
the  ear,  and  the  malar  bone  is  to  be  sawed  through  in  front  of  the  mas- 
3 


26  ANATOMY    OP    THE    HEAD    AND    NECK. 

seter  muscle;  this  muscle  being  partially  detached  from  the  surface 
of  the  ramus  of  the  jaw,  and  turned  downward  with  the  portion  of 
the  zygoma  and  malar  bone,  and  a  layer  of  fat  and  soft  cellular  tissue 
removed,  the  whole  temporal  muscle  will  be  exposed. 

The  TEMPORAL  MUSCLE  arises  from  the  temporal  aponeu- 
rosis  and  from  the  surface  of  the  depression  on  the  side  of 
the  skull  known  as  the  temporal  fossa.  Its  fibres  converge 
to  form  a  strong,  flat  tendon,  which  is  inserted  into  all  the 
inner  surface  of  the  coronoid  process  of  the  inferior  maxil- 
lary bone,  from  its  apex  to  near  the  last  molar  tooth. 


DISSECTION  III. 

DURA   MATER   AND    SINUSES. 

The  removal  of  the  calvaria  may  be  accomplished  by  breaking 
through  the  skull  on  a  line  just  above  the  frontal  sinuses  and  tlie 
tops  of  the  ears,  with  the  sharp  part  of  a  French  hammer,  or  it  may 
be  done  more  neatly  with  a  saw,  the  track  for  which  has  been  marked 
out  by  the  aid  of  a  string  tied  round  the  head.  The  saw  is  to  be  carried 
through  the  outer  table  of  the  bone  only,  and  the  inner  one  fractured 
by  a  chisel  and  mallet ;  this  saves  the  membranes  of  the  brain  from 
being  wounded,  but  does  not  leave  the  bones  in  so  neat  a  condition 
for  preservation,  when  that  is  desired.  The  sensation  communicated 
to  the  hand  by  the  saw,  and  the  color  of  the  bone-dust,  tell  the  ope- 
rator when  he  has  got  through  the  outer  table  and  reached  the  vascular 
diploe  between  the  two  tables.  The  application  of  very  considerable 
force  will  be  required,  by  either  prying  or  pulling  with  a  hook  or 
chisel  introduced  into  the  line  of  the  incision,  to  effect  the  detachment 
of  the  calvaria  from  the  membranes  adherent  to  it. 

The  DURA  MATER  is  the  most  external  of  the  cerebral 
membranes;  it  acts  as  periosteum  to  the  bones  of  the  skull 
and  as  a  support  to  the  brain  ;  it  is  rough  externally,  where 
it  is  torn  from  the  calvaria,  and  especially  so  along  the  line 
of  the  sutures ;  parts  of  it  are  occasionally  left  adhering 
to  the  detached  calvaria.  Upon  its  surface  along  the 
median  line  some  small  fibrous  bodies,  called  PaccJiionian 
glands,  will  be  noticed ;  they  are  wanting  in  infancy  and 
most  numerous  in  old  age ;  depressions  in  the  bone  corres- 
ponding to  them  will  sometimes  be  found. 

The  dura  mater  should  be  cut  with  scissors  along  the 
margin  of  the  sawed  skull  except  at  the  median  line  in 
front  and  behind.  The  two  flaps  thus  formed  may  be 
turned  up  on  to  the  top  of  the  brain.  It  will  now  be  seen 


DUEA    MATER    AND     SINUSES.  27 

that  its  inner  surface  is  smooth  and  polished ;  this  is  due 
to  a  serous  coat  which  is  the  parietal  part  of  the  arachnoid, 
a  serous  membrane  investing  the  brain  and  reflected  upon 
the  dura  mater,  and  which  will  be  more  particularly  spoken 
of  hereafter.  The  dura  mater  is  therefore  a  nbro-serous 
membrane.  By  separating  the  hemispheres  of  the  brain 
it  will  be  seen  that  a  process  of  the  dura  mater  penetrates 
like  a  septum  between  them  :  this  is  called  the falx  cerebri. 
Narrow  in  front,  it  is  attached  to  the  crista  galli  of  the 
ethmoid  bone ;  broader  posteriorly,  it  is  continuous  with  a 
horizontal  expansion  of  the  dura  mater  lying  between  the 
cerebrum  and  cerebellum,  called  the  tentorium ;  its  superior 
border  is  attached  along  the  vertex  of  the  skull,  and  the  in- 
ferior, which  is  concave  and  free,  nearly  reaches  the  corpus 
callosum  of  the  brain.  The  falx  sometimes  presents  perfo- 
rations of  various  sizes,  or  a  rarefaction  of  its  fibres,  which 
give  it  a  lace-like  appearance ;  more  rarely  a  solution  of 
continuity,  sufficient  to  allow  the  hemispheres  of  the  brain 
to  come  in  contact  with  each  other,  has  been  noticed. 

The  superior  longitudinal  sinus  occupies  the  convex 
border  of  the  falx,  and  may  be  laid  open  with  the  scissors  ; 
it  extends  from  the  crista  galli  to  the  internal  occipital  pro- 
tuberance, is  triangular  in  shape,  and  perforated  by  n  umerous 
small  veins  ;  in  its  interior,  transverse  fibrous  bands,  called 
chordae  Willisii,  cross  it  here  and  there,  and  occasionally 
Pacchionian  glands  are  found  within  the  sinus.  It  termi- 
nates posteriorly  at  the  torcular  Herophili.  The  inferior 
longitudinal  sinus  occupies  the  concave  border  of  the  falx  ; 
this  terminates  in  the  straight  sinus  of  the  tentorium, 
which  also  continues  to  the  torcular  Herophili,  the  common 
centre  of  several  sinuses,  the  situation  of  which  corres- 
ponds to  the  internal  occipital  protuberance.  The  straight 
sinus  receives  the  venae  Galeni,  which  come  from  the  inte- 
rior of  the  brain. 

The  brain  must  now  be  removed.  The  head  should  be  allowed  to 
depend  as  much  as  possible,  and  the  operation  is  to  be  commenced  by 
the  division  of  the  anterior  attachment  of  the  falx  ;  this  is  to  be  raised 
and  thrown  backward,  but  not  detached  posteriorly;  in  reflecting  this, 
several  veins,  entering  the  superior  longitudinal  sinus,  will  necessarily 
be  divided. 

The  examination  of  the  arteries  at  the  base  of  the  brain  is  not 
always  easy  in  the  subject  which  is  used  for  the  study  of  other  parts 
in  the  same  region.  If  the  brain  is  too  soft  to  be  examined  with 
benefit,  it  is  much  better  to  leave  the  arteries  in  connection  with  the 
skull.  The  softened  cerebral  matter  left  attached  to  them  may  be. 


28  ANATOMY    OF    THE    HEAD    AND     NECK. 

best  removed  by  a  stream  of  water  from  a  syringe  or  squeezed  sponge. 
In  a  fresh  brain,  or  one  which  will  harden  well,  they  should  be  studied 
in  connection  with  the  base  of  the  brain  ;  in  that  connection  they  will 
be  described. 

The  anterior  lobes  are  to  be  carefully  lifted  by  the  fingers,  together 
with  the  olfactory  bulbs  from  each  side  of  the  crista  galli.  The 
carotid  arteries,  optic  and  motor  oculi  nerves  are  to  be  divided  on 
each  side  of  the  processus  olivaris,  and  the  pituitary  gland  lifted  out 
of  the  sella  turcica  ;  this  sometimes  cannot  be  done,  and  then  its  pe- 
dicle must  be  divided.  The  hemispheres  being  supported  in  the  left 
hand,  and  gradually  allowed  to  roll  out  of  the  cranial  cavity,  the  ten- 
torium  is  brought  into  view,  and,  just  in  front  of  its  anterior  margin, 
the  fourth  or  trochlearis  nerve ;  this  is  to  be  divided,  and  the  ten- 
toriuin  is  to  be  detached  from  the  petrous  portion  of  the  temporal 
bone  by  cutting  as  close  to  its  insertion  thereto  as  possible.  The  fifth 
nerve  is  next  brought  into  view ;  the  sixth,  small  and  slight,  near  the 
median  line  of  the  clivus  Blurnenbachii  ;  more  externally  the  seventh 
pair,  composed  of  two  parts,  the  facial  and  auditory  ;  below  this  the 
three  trunks  of  the  eighth  pair ;  the  upper  being  the  glosso-phary  ngeal , 
the  flat  band  next  below,  the  pneumogastric  ;  and  the  one  ascending 
from  the  spinal  canal,  the  spinal  accessory.  These  being  divided,  as 
well  as  the  ninth,  which  is  the  remaining  one,  the  vertebral  arteries 
are  to  be  cut  off  close  to  the  spinal  cord.  The  spinal  cord  is  to  be  cut 
across,  with  the  spinal  nerves  on  each  side,  as  far  down  the  canal  as 
possible,  and  the  brain  will  then  roll  out  of  the  cranial  cavity. 

The  brain  should  be  laid  in  a  basin  with  the  base  uppermost ;  it 
should  be  immersed  in  alcohol  to  harden  and  preserve  it,  and  covered 
with  a  piece  of  doubled  cotton  cloth.  The  cloth  will  keep  it  wet  by 
imbibition,  if  there  is  not  alcohol  enough  to  cover  it. 

It  is.  however,  to  be  borne  in  mind  that  the  brain  softens  very  soon 
after  death,  and  that,  unless  early  removed,  it  may  be  unfit  for  dissec- 
tion. A  portion  of  each  hemisphere  may  be  shaved  off,  in  order  to 
give  the  spirit  a  better  opportunity  to  penetrate  ;  but  even  this  may 
not  prevent  its  decomposition  in  some  of  its  deep-seated  parts.  The 
autopsy-room  is  the  best  place  for  the  study  of  the  brain,  as  it  can 
always  there  be  seen  in  its  fresh  and  naturally  firm  condition. 

The  dura  mater  at  the  base  of  the  cranial  cavity  will  be 
found  very  adherent,  on  account  of  the  sutures  into  which 
it  penetrates,  and  the  foramina  through  which  it  is  con- 
tinued to  form  the  sheath  of  the  nerves ;  it  is  also  prolonged 
downward  into  the  spinal  canal  where  it  forms  a  loose 
investment  of  the  spinal  cord.  The  tentorium,  if  replaced, 
will  be  found  to  separate  the  spaces  occupied  by  the  cere- 
brum and  cerebellum,  and  to  be  attached  along  the  trans- 
verse groove  of  the  occipital  bone,  the  sharp  edge  of  the 
petrous  portion  of  the  temporal  bone,  and  to  the  posterior 
clinoid  processes  of  the  sphenoid. 

In  the  attachment  of  the  tentorium  to  the  occipital  bone 
will  be  seen  the  lateral  sinuses;  at  the  base  of  the  petrous 


DUE  A    MATER    AND     SINUSES.  29 

portion  of  the  temporal  bone  these  sinuses  turn  downward, 
and  pass  through  the  posterior  foramen  lacerum ;  just 
before  entering  the  foramen  the  inferior  petrosal  sinus  joins 
the  lateral  sinus,  and  the  two  united  become  the  internal 
jugular  vein. 

The  inferior  petrosal  sinus  is  the  continuation  backward 
of  the  cavernous  sinus  ;  it  passes  along  the  lower  border  of 
the  petrous  portion  of  the  temporal  bone,  and  terminates 
as  above  described.  The  superior  petrosal  sinus  is  of  small 
size,  and  lies  along  the  upper  border  of  the  petrous  bone 
in  the  attached  portion  of  the  tentorium ;  it  establishes 
another  communication  between  the  cavernous  and  lateral 
sinuses,  by  entering  the  latter  near  the  base  of  the  petrous 
bone. 

Projecting  below  the  tentorium  is  the  falx  cerebelli, 
which  separates  the  two  hemispheres  of  the  cerebellum  as 
the  falx  cerebri  does  those  of  the  cerebrum  ;  it  ends  at  the 
foramen  magnum,  and  is  attached  along  the  middle  line  of 
the  occipital  bone.  In  the  attached  border  of  this  falx  may 
be  found  two  small  sinuses,  called  the  occipital  sinuses, 
which  terminate  in  the  torcular  Herophili. 

The  cavernous  sinuses  are  situated  on  each  side  of  the 
sell  a  turcica,  and  are  so  called  from  the  existence,  in  their 
interior,  of  trabeculae,  like  those  of  cavernous  structures  in 
other  parts  of  the  body.  In  the  internal  wall  of  the  sinus 
is  the  internal  carotid  artery,  covered  by  minute  nervous 
ii laments  of  the  carotid  plexus  of  the  sympathetic  nerve, 
and  crossed  by  the  sixth  or  abducens  nerve  ;  in  the  external 
wall  of  the  sinus  are  the  third  (motor  oculi),  fourth  (tro- 
chlearis),  and  ophthalmic  branch  of  the  fifth  or  trifacial 
nerve. 

The  cavernous  sinuses  of  the  two  sides  are  connected  by 
the  circular  sinuses,  which  surround  the  pituitary  gland  ; 
the  transverse,  or  hasilar  sinus,  which  lies  upon  the  basilar 
portion  of  the  occipital  bone,  sometimes  unites  the  cavern- 
ous and  sometimes  the  petrosal  sinuses ;  anteriorly,  they 
receive  the  ophthalmic  veins,  which,  after  collecting  the 
blood  from  the  eye  and  structures  within  the  orbit,  enter 
the  sinus  through  the  sphenoidal  fissure. 

The  PITUITARY  BODY  should  be  sought  for  in  the  sella 
turcica  and  removed  for  examination.  It  is  a  reddish- 
gray,  solid  bod}r,  closely  fixed  in  its  location  by  the  dura 
mater  ;  it  is  composed  of  two  lobes,  the  anterior  of  which 
is  the  largest ;  and  is  connected  with  the  infundibulum  of 


30  ANATOMY    OP    THE     HEAD    AND     NECK. 

the  brain  by  a  peduncle,  which  should  be  noticed.  In  the 
foetus  the  pituitary  body  is  hollow,  and  communicates  with 
the  third  ventricle  through  the  infimdibuhim.  It  was  by 
virtue  of  this  communication  that  Yesalius  believed  the 
fluid  of  the  ventricles  was  transmitted  to  the  pituitary 
body,  and  from  it  through  the  sphenoidal  sinuses  to  the 
nasal  fossae,  thus  causing  the  disease  called  pituita,  or 
catarrh  ;  a  theory  which  charlatans  still  find  for  their  ad- 
vantage to  maintain. 

The  dura  mater  is  supplied  by  a  number  of  arteries 
called  meningeal.  The  anterior  meningeal,  an  offset  from 
the  ethmoid  branch  of  the  internal  carotid,  is  a  small 
artery  which  enters  the  skull  by  a  foramen  between  the 
ethmoid  and  frontal  bones,  and  is  distributed  to  the  dura 
mater  in  that  vicinity.  The  middle  meningeal  artery  is  a 
branch  of  the  internal  maxillary  ;  it  enters  the  skull  by  the 
spinous  foramen  of  the  sphenoid  bone,  and  passing  into  a 
deep  groove  in  the  inferior  angle  of  the  parietal  bone, 
spreads  over  the  side  of  the  cranial  cavity ;  the  meningea 
parva,  from  the  same  source,  enters  by  the  foramen  ovale, 
and  is  distributed  to  the  middle  cranial  fossa.  The  in- 
ferior meningeal  arteries  are  branches  from  the  ascending 
pharyngeai  and  occipital,  which  enter  by  the  foramen 
lacerum  posterius,  and,  together  with  ihe  posterior  menin- 
geal, from  the  vertebral  artery,  supply  the  middle  and  pos- 
terior cranial  fossae. 

The  vertebral  arteries  will  be  seen  entering  the  foramen 
magnum,  where  they  pierce  the  dura  mater.  The  arteries 
of  the  two  sides  converge  in  front  of  the  medulla  oblon- 
gata,  and  become  united  in  one  trunk,  the  basilar,  which 
will  be  described  with  the  base  of  the  brain.  The  vertebral 
artery  gives  off  many  small  branches,  and  one  of  some 
size,  the  posterior  meningeal,  to  the  cerebellar  fossa  and 
the  falx  cerebelli. 

The  internal  carotid  artery  perforates  the  base  of  the 
skull,  at  the  apex  of  the  petrous  portion  of  the  temporal 
bone ;  given  off  from  the  common  carotid  in  the  neck,  it 
ascends  to  the  carotid  foramen  in  the  temporal  bone,  and 
pursuing  a  tortuous  course  in  an  osseous  canal  through 
that  bone,  enters  the  cranial  cavity.  The  cranial  part  of 
the  vessel  describes  an  S-like  curve  at  the  side  of  the  sella 
turcica  where  it  lies  in  the  cavernous  sinus  ;  near  the  ante- 
rior clinoid  process  it  gives  off  the  ophthalmic  artery,  and 
then,  turning  upward,  divides  into  branches  to  supply  the 


ARTERIES    AND     MUSCLES    OF    THE    ORBIT.       31 

brain.  As  it  winds  through  the  cavernous  sinus  it  is  sur- 
rounded by  nervous  plexuses  derived  from  the  sympathetic 
nerve  of  the  neck  ;  the  branches  of  these  plexuses  are  very 
minute,  and  in  an  injected  subject  are  not  likely  to  be 
found  ;  they  are  called  the  carotid  and  cavernous  plexuses, 
the  former  being  on  the  outer  side  at  the  entrance  of  the 
sinus,  and  the  latter  close  to  the  root  of  the  anterior  clinoid 
process,  which  should  be  cut  away  to  examine  it. 

ARTERIES   AND    MUSCLES   OF    THE   DRBIT. 

In  order  to  examine  the  ophthalmic  artery  and  other  contents  of 
the  orbit,  the  frontal  bone  should  be  sawed  down  to  the  orbit  at  its 
inner  as  well  as  at  its  outer  angle,  and  the  two  incisions  continued 
backward  with  a  chisel  till  they  meet  near  the  optic  foramen  ;  the 
bone  being  turned  down  over  the  eye,  but  not  removed,  the  orbit  is 
exposed,  filled  with  a  soft  delicate  fat.  The  muscles  and  arteries 
require  patience  for  their  dissection  ;  these  may  be  dissected  upon  one 
side,  and  the  nerves  upon  the  other.  The  eye  of  any  large  animal, 
if  removed  with  all  the  contents  of  the  orbit,  permits  the  verification, 
on  a  larger  scale3  of  many  of  the  points  about  to  be  described. 

The  ophthalmic  artery  enters  the  orbit  at  the  optic  fora- 
men on  the  outer  side  of  the  optic  nerve  ;  it  gives  off 
numerous  small  branches  not  always  reached  by  the  injec- 
tion. Its  first  branch  is  the  lachrymal;  this  lies  along  the 
upper  border  of  the  external  rectus  muscle,  in  company 
with  the  lachrymal  nerve ;  it  is  distributed  to  the  lachrymal 
gland  and  eyelids.  The  supra-orbital  branch  rests  upon  the 
levator  palpebrse  muscle,  and  passes  forward  through  the 
supra-orbital  foramen,  where  it  divides  upon  the  forehead, 
and  is  distributed  to  the  muscles  and  integument.  The 
ethmoidal  branches,  two  in  number,  pass  through  the  eth- 
moiclal  foramina,  and  are  distributed  to  the  dura  mater 
and  nasal  fossae.  The  palpebral  are  given  oft'  by  a  common 
trunk  which  divides  into  two  branches  near  the  inner  angle 
of  the  C3'elids,  to  which  they  are  distributed.  The  frontal 
branch  emerges  at  the  inner  angle  of  the  eye,  and  is  dis- 
tributed to  the  forehead.  The  nasal  also  emerges  at  the 
inner  angle,  and  divides  into  two  branches,  one  of  which 
anastomoses  with  the  angular  or  terminal  branch  "of  the 
facial,  and  the  other  under  the  name  of  the  dorsalis  nasi  is 
distributed  to  the  nose.  The  muscular  branches  supply 
the  muscles,  and  give  off  some  small  twigs  to  the  eyeball, 
called  anterior  ciliary.  The  short  ciliary  branches  enter 
the  eyeball  around  the  optic  nerve  ;  two  of  these,  one  on 
each  side,  piercing  the  sclerotic,  farther  forward,  are  called 


32  ANATOMY    OF    THE     HEAD    AND     NECK. 

the  long  ciliary  arteries.  The  arleria  centralis  retinae  is  a 
very  small  branch  which  perforates 'the  optic  nerve,  and  is 
distributed  to  the  interior  of  the  eyeball. 

The  dissection  of  these  arteries  will  have  in  a  measure 
effected  the  dissection  of  the  muscles  of  the  orbit. 

The  LEVATOR  PALPEBR^E  is  the  most  superficial  of  the 
orbital  muscles  ;  it  arises  from  the  roof  of  the  orbit  in  front 
of  the  optic  foramen  and  is  inserted  by  a  broad  tendon  into 
the  tarsal  cartilage  of  the  upper  eyelid. 

This  muscle  is  to  be  divided,  and  its  two  ends  are  to  be  reflected. 

Four  straight  muscles  surround  the  optic  nerve,  and  are 
named  from  their  position  SUPERIOR  and  INFERIOR,  EX- 
TERNAL and  INTERNAL  RECTI  MUSCLES  ;  with  the  exception 
of  the  external  rectus,  they  arise  posteriorly  from  the  cir- 
cumference of  the  optfc  foramen  and  sheath  of  the  optic 
nerve  by  a  common  attachment ;  the  external  rectus  arises 
by  two  heads,  the  upper  one  joining  the  superior  rectus, 
and  the  lower  the  inferior  rectus,  springing  also  from  the 
lower  border  of  the  sphenoidal  fissure ;  between  these 
origins  pass  the  motor  oculi  (third),  the  abducens  (sixth), 
and  the  nasal  branch  of  the  ophthalmic  nerve,  to  enter  the 
orbit.  The  recti  muscles  are  all  inserted,  at  equi-distant 
intervals,  into  the  sclerotic  coat  of  the  eyeball,  about  a 
quarter  of  an  inch  from  the  cornea. 

The  SUPERIOR  OBLIQUE  MUSCLE,  situated  in  the  upper 
and  inner  part  of  the  orbit,  is  a  small  rounded  muscle 
arising  from  the  inner  side  of  the  optic  foramen ;  it  ends 
anteriorly  in  a  tendon  which  passes  through  a  loop  attached 
to  a  depression  in  the  frontal  bone  at  the  inner  part  of 
the  orbit,  and  is  thence  reflected  backward  and  outward, 
between  the  globe  of  the  eye  and  the  belly  of  the  superior 
rectus,  to  be  inserted  by  a  broad  and  flat  tendon  into  the 
sclerotic,  between  the  superior  and  external  recti  muscles. 
From  this  pulley-like  peculiarity  the  superior  oblique  is 
sometimes  called  the  trochlearis  muscle.  The  loop  is  a 
fibro-cartilaginous  ring  about  an  eighth  of  an  inch  in  width, 
and,  as  well  as  the  tendon  which  plays  through  it,  is  lined 
with  a  sjmovial  membrane. 

In  order  to  examine  the  next  muscle,  the  optic  nerve  and  the  recti 
muscles  must  be  divided  near  their  origin,  and  the  eye  gently  turned 
out  of  its  socket,  so  as  to  expose  its  inferior  surface. 

The  INFERIOR  OBLIQUE  MUSCLE  arises  from  the  superior 
maxillary  bone,  between  the  margin  of  the  orbit  and  the 


CRANIAL  NERVES  AT  EXIT  FROM  SKULL.   33 

lachrymal  groove ;  it  then  passes  across  the  orbit,  between 
the  globe  of  the  eye  and  the  inferior  and  external  recti 
muscles,  and  is  inserted  into  the  external  and  posterior 
part  of  the  sclerotic.  This  is  the  only  muscle  of  the  eye 
which  does  not  arise  from  the  bottom  of  the  orbit. 

In  dissecting  the  e}re  of  a  sheep,  ox,  or  calf,  the  student 
is  often  puzzled  by  an  additional  muscle,  of  which  he  finds 
no  description.  It  is  a  suspensor  or  retractor  of  the  eye- 
ball, and,  with  the  exception  of  man  and  the  apes,  appears 
to  belong  to  all  the.  mammalia ;  in  most  instances  it  is  a 
quadrifid  muscle,  but  in  the  ruminantia  it  coalesces  into  a 
single  infundibuliform  muscle,  embracing  the  optic  nerve, 
and  attached  anteriorly  to  the  sclerotic,  behind  the  cornea. 


DISSECTION  IY. 

CRANIAL   NERVES   AT    THEIR   EXIT    FROM   THE   SKULL. 

Paragraphs  marked  with  an  asterisk  can  hardly  be  verified  in  an 
ordinary  dissection. 

Soemmering  counts  the  cranial  nerves  at  their  points  of 
exit  at  the  base  of  the  skull  as  twelve  pairs,  enumerating 
each  nerve  separately.  Willis  makes  them  but  nine,  in- 
cluding in  one  nerve  all  the  trunks  contained  in  the  same 
aperture  of  the  skull.  The  latter  division  is  the  one 
adopted. 

The  cranial  nerves,  as  they  enter  their  foramina,  are  in- 
vested by  a  process  of  the  dura  mater,  which  constitutes  a 
sheath  for  them ;  the  pia  mater  also  is  prolonged  upon 
them,  but  both  membranes  are  soon  lost  in  the  surrounding 
tissues.  The  arachnoid  is  reflected  backward  upon  the 
internal  surface  of  the  cranial  cavity. 

The  FIRST,  or  OLFACTORY  NERVE,  is  soft  and  pulpy,  and 
is  often  lost  in  the  manipulation  of  removing  the  brain ;  it 
lies  upon  the  cribriform  plate  of  the  ethmoid  bone,  and 
toward  its  extremit}'  assumes  a  bulbous  shape ;  it  sends  a 
large  number  of  fine  filaments,  through  the  foramina  of  the 
bone  beneath,  to  supply  the  mucous  membrane  of  the  nasal 
fossa?. 

The  SECOND,  or  OPTIC  NERVE,  diverging  from  its  com- 
missure, as  the  conjunction  with  its  fellow  is  called,  enters 


34  ANATOMY    OF    THE    HEAD    AND    NECK. 

the  orbit  through  the  optic  foramen.  This  nerve  is  large 
and  of  a  white  color;  it  is  accompanied  by  the  ophthalmic 
artery,  and  invested  with  a  firm  sheath  from  the  dura 
mater;  it  has  no  branches,  and  continues  forward  to  the 
eyeball,  where  it  expands  into  the  retina. 

The  orbital  plate  of  the  frontal  bone,  on  the  opposite  side  to  that 
used  for  the  dissection  of  the  muscles  and  arteries  of  the  orbit,  should 
be  broken  through  with  a  chisel,  in  such  a  way  as  to  make  a  trian- 
gular opening  into  the  cavity,  the  base  of  which,  an  inch  and  a  half 
wide,  should  be  as  far  forward  as  possible ;  the  apex  should  lay  bare 
the  optic  foramen,  but  without  injuring  the  nerves. 

As  the  third  and  fourth  nerves,  and  a  branch  of  the  fifth,  lie  in  the 
walls  of  the  cavernous  sinus,  the  dura  mater  which  constitutes  it 
must  be  dissected  away.  The  fifth  nerve  should  also  be  cleared  from 
the  dura  mater,  and  the  Gasserian  ganglion  which  lies  upon  the  apex 
of  the  petrous  portion  of  the  temporal  bone  in  the  middle  fossa,  and 
into  which  the  fifth  nerve  soon  expands,  should  be  dissected  cleanly, 
and  its  three  large  trunks,  the  ophthalmic,  and  the  superior  and 
inferior  maxillary,  traced  to  their  points  of  exit,  the  sphenoidal  fissure, 
the  foramina  ovale  and  rotundum. 

The  THIRD,  or  MOTOR  OCULT  NERVE,  pierces  the  dura 
mater  just  in  front  of  the  posterior  clinoid  processes;  pur- 
suing its  course  in  the  external  wall  of  the  cavernous  sinus, 
it  enters  the  orbit  through  the  sphenoidal  fissure,  passing 
between  the  two  heads  of  the  external  rectus  muscle,  and 
divides  into  two  branches.  The  superior  branch  supplies 
the  superior  rectus  muscle  and  the  levator  palpebrae.  The 
inferior  branch  supplies  the  internal  and  inferior  rectus 
and  the  inferior  oblique  muscles.  It  will  thus  be  seen  that 
this  nerve  supplies  all  the  muscles  of  the  eye,  except  the 
external  rectus  and  superior  oblique,  each  of  which  has  a 
special  nerve.  These  branches  are  very  small,  and,  lying 
in  the  midst  of  fat,  require  great  patience  and  considerable 
skill  to  dissect. 

*  The  inferior  branch  of  the  motor  oculi  nerve  sends  a 
branch  of  communication  to  the  lenticular  ganglion,  a 
small  rounded  body,  the  size  of  a  pin's  head,  placed  at  the 
back  part  of  the  orbit,  between  the  optic  nerve  and  exter- 
nal rectus  muscle,  and  commonly  on  the  outer  side  of  the 
ophthalmic  artery.  This  ganglion  gives  off  the  ciliary 
nerves,  which  pierce  the  sclerotic  in  company  with  the 
short  ciliary  arteries  around  the  optic  nerve. 

The  FOURTH,  or  TROCHLEARIS  NERVE,  is  very  small,  and 
sometimes  puzzling  to  find.  It  pierces  the  dura  mater 
close  to  the  third  nerve,  and  passes  along  the  outer  wall  of 


CRANIAL    NERVES    AT    EXIT    FROM    SKULL.      35 

the  cavernous  sinus  to  the  sphenoidal  fissure ;  entering  the 
orbit,  it  crosses  the  levator  palpebrse  at  its  origin,  and 
supplies  the  trochlearis  or  superior  oblique  muscle. 

The  FIFTH,  or  TRIFACTAL  NERVE,  the  largest  of  the  nine 
pairs  of  nerves,  consists  of  two  parts  or  roots.  These 
two  portions  pass  through  the  tentorium  close  to  the  apex 
of  the  petrous  portion  of  the  temporal  bone ;  the  larger 
division,  immediately  on  reaching  the  middle  fossa  of  the 
skull,  expands  into  a  flattened  ganglion,  the  Gasserian ; 
the  smaller  division  lies  beneath  the  ganglion,  and  is  only 
seen  by  turning  it  over.  These  two  roots  are  distinct  from 
each  other,  and  the  smaller  one  may  be  traced  onward  to 
the  inferior  maxillary  nerve  which  it  joins  outside  of  the 
cranium. 

The  Gasserian  ganglion  gives  off  three  branches — the 
ophthalmic,  and  the  superior,  and  inferior  maxillary 
nerves. 

The  ophthalmic  nen-e,  arising  from  the  upper  portion  of  the  ganglion, 
passes  through  the  onter  wall  of  the  cavernous  sinns,  and  enters  the 
orbit  through  the  sphenoidal  fissure.  It  divides  into  three  branches 
— nasal,  frontal,  and  lachrymal. 

*  The  nasal  branch  passes  between  the  two  heads  of  the  external 
rectus  muscle,  crosses  the  optic  nerve,  and  enters  the  anterior  eth- 
moidal  foramen  ;  it  then  reappears  in  the  cranium  at  the  side  of  the 
crista  galli,  and  enters  the  nasal  cavity,  in  front  of  the  cribriform 
plate,  to  be  distributed  to  the  mucous  membrane  and  integument  of 
the  nose.-    As  the  nasal  nerve  enters  the  orbit,  it  sends  a  branch  to 
the  lenticular  ganglion.     The  frontal  branch  passes  forward  upon  the 
levator   palpebra?    muscle    to   the    supra-orbital    foramen,   where    it 
emerges  to  supply  the  integument  of  the  forehead.     The  lachrymal  is 
the  smallest  of  the  three  branches.     It  passes  along  the  upper  border 
of  the  external  rectus  muscle  to  the  lachrymal  gland  and  upper  eye- 
lid, to  which  it  is  distributed. 

The  superior  maxillary  nerve,  the  second  or  middle  division  of  the 
fifth  pair,  passes  out  at  the  foramen  rotundum,  crosses  the  spheno- 
maxillary  fissure,  and  enters  the  orbit  by  the  canal  in  its  floor,  in 
company  with  the  infra-orbital  artery,  one  of  the  terminal  branches 
of  the  internal  maxillary  ;  they  both  emerge  at  the  infra-orbital  fora- 
men (p.  10),  beneath  the  levator  labii  superioris  muscle,  and,  forming 
a  plexus  with  branches  of  the  facial  nerve,  supply  the  lower  eyelid, 
upper  lip,  nose,  and  cheek. 

*  This  nerve  gives  off  an  orbitar  branch,  which,  entering  the  orbit 
through   the  spheno-maxillary  fissure,  divides    into    two   branches; 
these  pass  through  foramina  in  the  malar  bone,  and  are  distributed  to 
the  temporal  fossa,  forehead,  and  cheek.     Dental  branches  also  pene- 
trate through  small  foramina  in  the  tuberosity  of  the  superior  max- 
illary bone    to    the   molar   teeth,  and   from    the    infra-orbital   canal 
through  the  lining  membrane  of  the  antruin  to  the  anterior  teeth. 


36  ANATOMY    OF    THE     HEAD    AND    NECK. 

These  branches,  as  well  as  that  portion  of  the  main  trunk  lying  in 
the  infra-orbital  canal,  cannot  of  course  be  seen  without  the  removal 
of  the  eyeball. 

The  inferior  maxillary  nerve  is  the  longest,  and  the  most  inferior  in 
point  of  position  of  the  three  trunks  into  which  the  fifth  pair  divides  ; 
as  it  passes  out  through  the  foramen  ovale  it  is  joined  by  the  second 
primary  root  of  the  fifth  nerve,  which  lies  behind  the  ganglion ;  it 
then  divides  into  muscular,  the  gustatory,  the  inferior  dental,  and 
the  auriculo-temporal  branches. 

The  SIXTH,  or  ABDUCENS  NERVE,  pierces  the  dura  mater 
on  the  clivus  Blumenbachii  of  the  sphenoid  bone ;  it  crosses 
the  cavernous  sinus,  enters  the  orbit  through  the  sphenoidal 
fissure,  and  passes  between  the  two  heads  of  the  external 
rectus  or  abducens  muscle,  to  which  it  is  distributed. 

The  SEVENTH  PAIR  consists  of  two  nerves,  the  FACIAL 
and  the  AUDITORY  ;  the  facial  is  called  the  portio  dura,  the 
auditory  the  portio  mollis,  the  former  being  of  a  dense,  the 
latter  of  a  soft  and  pulpy  structure.  Both  of  these  nerves 
enter  the  temporal  bone  at  the  meatus  auditorius  interims. 

In  order  to  study  these  nerves  properly,  a  temporal  bone  should  be 
immersed  in  strong  alcohol,  and  afterward  softened  in  hydrochloric 
acid ;  it  can  then  be  cut  with  a  knife,  and  its  canals  followed  out. 

The  facial  nerve  is  the  smallest  of  the  two  trunks  ;  after 
entering  the  meatus  auditorius  internus,  it  passes  through 
the  aqueduct  of  Fallopius  and  emerges  at  the  stylo-mastoid 
foramen ;  it  there  divides  into  two  branches,  the  temporo- 
facial  and  the  cervico-facial ;  these  have  been  already  de- 
scribed (p.  23).  While  in  the  aqueduct  of  Fallopius,  this 
nerve  forms  a  ganglionic  enlargement,  called  the  intumes- 
centia  gangliformis.  A  small  branch  of  the  Yidian  nerve, 
which  passes  backward  beneath  the  Gasserian  ganglion, 
enters  the  hiatus  Fallopii  to  join  the  intumescentia  ;  this  is 
called  the  superficial  petrosal  nerve. 

*  The  auditory  nerve  enters  the  meatus  auditorius  inter- 
nus, and  dividing  into  two  branches,  the  cochlear  and  vesti- 
bular,  is  distributed  to  the  internal  auditory  apparatus. 

The  EIGHTH  PAIR  is  composed  of  three  nerves,  the 
GLOSSO-PHARYNGEAL,  PNEUMOGASTRIC,  and  SPINAL  ACCES- 
SORY ;  these  all  pass  out  at  the  foramen  lacerum  posterius. 

The  glosso-pharyngeal  nerve  passes  through  a  distinct 
canal  of  the  dura  mater  in  the  above-named  foramen,  and  lies 
at  its  innermost  extremity.  That  portion  of  the  nerve  lying 
in  the  jugular  fossa  presents  two  gangliform  swellings,  the 
superior  being  called  the  ganglion  jug ulare  and  the  inferior 


CRANIAL  NERVES  AT  EXIT  FROM  SKULL.   3t 

the  ganglion  petrosum,  or  ganglion  of  Andersch.  The  gan- 
glion of  Andersch  gives  off  the  tympanic,  or  Jacobson's 
nerce  ;  this  enters  a  small  bony  canal  in  the  jugular  fossa, 
and  is  distributed  to  the  tympanum,  forming  the  tympanic 
plexus,  which  communicates  with  the  sympathetic  and  with 
the  fifth  pair  of  nerves.  One  or  two  other  minute  branches 
are  also  given  off  from  the  ganglion  or  its  vicinity.  The 
glosso-pharyngeal  nerve  is  distributed  to  the  base  of  the 
tongue,  the  fauces,  and  the  pharynx. 

*  The  pneumogastric,  or  par  vagum  nerve,  passes  out  of 
the  foramen  lacerum  posterius  in  a  sheath  common  to  it 
and  the  spinal  accessory  nerve ;  it  is  the  longest  of  the 
three  nerves.   In  the  foramen,  it  has  a  large  ganglion  called 
the  ganglion  of  the  root,  in  contradistinction  to  the  ganglion 
of  the  trunk,  which  is  formed  after  it  has  escaped  from  the 
skull. 

*  The  spinal  accessory  nerve  passes  out  of  the  foramen 
lacerum  posterius  with  the  pneumogastric ;  it  has  no  gan- 
glion.    In  the  jugular  fossa  it  divides  into  two  branches, 
one  of  which  sends  a  few  filaments  to  the  upper  ganglion 
of  the  pneumogastric,  with  the  trunk  of  which  it  becomes 
continuous  below  the  second  ganglion,  and  the  other  de- 
scends to  the  sterno-mastoid  muscle,  which  it  perforates, 
and  to  which,  as  well  as  the  trapezius  muscle,  it  is  distri- 
buted. 

The  NINTH,  or  HYPOGLOSSAL  NERVE,  consists  of  two 
bundles,  which  pass  out  at  the  anterior  condyloid  foramen 
by  separate  orifices  of  the  dura  mater.  These  unite  after 
emerging  from  the  skull,  and  the  nerve  is  distributed  to  the 
muscles  of  the  tongue. 


According  to  the  arrangement  which  this  book  proposes, 
the  subject  is  now  to  be  turned  over  for  the  dissection  of 
the  back :  if  the  student  has  kept  up  with  his  companions, 
and  accomplished  the  previous  dissections,  the  turning- 
may  be  done  without  inconvenience.  The  muscles  of  the 
back  of  the  neck  are  given  with  those  of  the  back,  in  Part 
Second,  Dissection  Y. 


38  ANATOMY    OF    THE     HEAD    AND     NECK. 

DISSECTION  V. 

SUPERFICIAL   CERVICAL   REGION. 

The  dissection  is  now  transferred  to  the  neck.  The  head  should 
hang  backward  by  its  own  weight ;  the  chain  hook  should  be  caught 
into  the  septum  of  the  nose,  and  by  it  the  head  should  be  rotated 
and  held  to  one  side,  as  far  as  it  is  possible  to  do  so;  this  ex- 
poses the  cervical  region,  and  puts  the  muscles  on  the  stretch.  An 
incision  is  made  along  the  median  line,  from  the  chin  to  the  sternum, 
and  another,  if  not  already  made,  along  the  rainus  of  the  jaw  ;  a  third 
is  carried  along  the  clavicle,  from  the  termination  of  the  first,  out- 
ward. The  skin  is  to  be  lifted  from  the  angle  at  the  sternum,  but  as 
the  fibres  of  the  platysma  are  often  very  thin  and  indistinct,  and  so 
pale  in  color  as  hardly  to  be  distinguished  from  the  fascia  between  it 
and  the  skin,  this  fascia  must  be  raised  with  such  care  as  to  insure 
the  demonstration  of  the  muscle,  however  feebly  it  may  be  developed. 

The  PLATYSMA  MYOIDES  arises  from  the  integument  in 
front  of  the  thorax,  below  the  clavicle ;  its  fibres  ascend 
obliquely  forward,  uniting  upon  the  median  line,  when  well 
developed,  with  those  of  the  other  side,  and  are  inserted 
into  the  chin,  the  angle  of  the  mouth,  and  the  integument 
of  the  face,  being  intimately  connected  with,  and  in  fact 
helping  to  form  several  of  the  facial  muscles. 

The  platysma  is  to  be  removed  without  disturbing  the  fascia,  or  the 
numerous  nerves  which  lie  upon  and  between  it  and  the  sterno- 
mastoid  muscle. 

The  removal  of  the  platysma-myoides  brings  the  cervical 
region  more  fairly  into  view.  It  will  be  seen  that  it  is 
quadrilateral,  and  that  its  boundaries  may  be  indicated  in 
a  general  way,  as,  superiorly,  the  ramus  of  the  jaw  and  the 
mastoid  process ;  inferiorly,  the  clavicle ;  posteriorly,  the 
edge  of  the  trapezius  muscle ;  and  anteriorly,  the  median 
line  of  the  neck. 

The  cervical  fascia  varies  in  distinctness  in  different 
subjects ;  it  surrounds  the  neck,  and  is  stronger  in  front  of 
than  behind  the  stern  o-mastoid  muscle,  which  it  encases. 
The  external  jugular  vein  lies  upon  it,  and  perforates  it  at 
its  lower  part,  and  the  branches  of  the  anterior  cervical 
plexus  of  nerves  lie  partly  upon  and  partly  beneath  the 
fascia. 

The  EXTERNAL  JUGULAR  YEIN  is  formed  by  the  union  of 
the  posterior  auricular  and  temporo-maxillary  veins,  veins 
of  the  integument  and  of  the  zygomatic  and  pterygoid 
fossae.  The  external  jugular  vein  is  of  variable  size;  it 


SUPERFICIAL    CERVICAL    REGION.  39 

descends  the  neck,  following  a  line  from  the  angle  of  the 
jaw  to  the  middle  of  the  clavicle,  crossing  the  sterno- 
mastoid  muscle,  and  penetrates  the  fascia,  just  at  the  side 
of  the  outer  border  of  the  clavicular  portion  of  that  muscle, 
terminating  in  the  subclavian  vein.  In  its  course  it  is  joined 
by  the  veins  which  accompany  the  supra-scapular  and  pos- 
terior scapular  arteries  in  the  posterior  part  of  the  neck. 
The  anterior  jugular  vein,  formed  by  a  series  of  small 
branches,  collects  the  blood  from  the  front  of  the  neck,  and 
descending  along  the  anterior  border  of  the  sterno-mastoid 
muscle,  sometimes  enters  the  external  jugular,  and  some- 
times passes  beneath  the  sterno-mastoid,  to  join  the  inter- 
nal jugular  or  subclavian  vein. 

The  cervical  fascia  is  to  be  removed  in  dissecting  the  nervous 
branches  which  ramify  in  this  region  ;  for  the  most  part  these  emerge 
behind  the  sterno-mastoid,  and  are  to  be  followed  to  their  origin  be- 
neath that  muscle  so  far  as  may  be,  without  dividing  it.  The  infra- 
maxillary  branches  of  the  cervico-facial  division  of  the  facial  nerve 
(p.  23)  will  be  found  beneath  the  platysma,  between  the  inferior 
maxilla  and  the  hyoid  bone. 

The  anterior  branches  of  the  four  upper  cervical  nerves 
communicate  with  each  other  by  loops,  and  these  loops, 
together  with  their  branches,  constitute  the  cervical  plexus  ; 
emerging  from  under  the  posterior  border  of  the  sterno- 
mastoid  muscle,  and  covered  in  by  the  platysma,  it  is  dis- 
tributed to  the  muscles  and  integument.  Its  branches  are 
divided  into  ascending,  descending,  and  deep. 

The  ascending  branches  are  three  in  number: — 

Superficialis  colli, 
Auricularis  magnus, 
Occipitalis  minor. 

The  snperficinlis  colli  nerve,  coming  from  the  second  and  third 
cervical  nerves,  emerges  behind  the  posterior  border  of  the  sterno- 
mastoid,  at  about  its  middle,  crosses  it  in  a  direction  obliquely 
upward,  and  divides  into  ascending  and  descending  branches,  which 
are  distributed  to  the  front  of  the  neck. 

The  auricnlaris  magnus  nerve  comes  also  from  the  second  and  third 
cervical  nerves,  and  emerges  at  the  posterior  border  of  the  sterno- 
mastoid,  on  the  superficial  surface  of  which  it  ascends,  in  close  relation 
with  the  external  jugular  vein,  to  the  parotid  gland,  where  it  divides 
into  two  branches,  the  anterior  being  distributed  to  the  external  ear, 
parotid  gland,  and  cheek  ;  the  posterior,  crossing  the  mastoid  process, 
supplying  the  back  part  of  the  external  ear  and  the  integument  in  its 
neighborhood. 

The  occipilal'ts  minor  nerve  arises  from  the  second  cervical  nerve,  and 


40      ANATOMY  OF  THE  HEAD  AND  NECK 

will  be  found  lying  upon  the  upper  part  of  the  posterior  border  of  the 
sterno-mastoid  muscle.  It  is  distributed  to  the  integument  of  the 
occipital  region,  and  anastomoses  with  the  occipitalis  major,  auricularis 
magnus,  and  posterior  branches  of  the  facial  nerve. 

The  descending  branches  of  the  cervical  plexus  come  from  the  third 
and  fourth  cervical  nerves,  and,  descending  between  the  sterno-mastoid 
and  trapezius  muscles,  are  named  acromial  and  clavicular,  being  dis- 
tributed to  the  integument  and  muscles  of  the  shoulder  and  anterior 
and  upper  part  of  the  thorax.  The  deep  branches  will  be  described 
hereafter.  They  are  chiefly  musciilar,  or  connecting  filaments  with 
the  pneumogastric,  sympathetic,  or  hypoglossal  nerves.  The  com- 
municans  noni  aud  the  phrenic  are  the  most  important. 

The  STERNO-MASTOID  MUSCLE  is  the  large  and  prominent 
muscle  which  characterizes  the  cervical  region ;  it  is  en- 
cased by  the  cervical  fascia,  and  is  crossed  superficially  by 
the  external  jugular  vein  and  the  branches  of  the  cervical 
plexus.  It  arises  by  two  heads,  separated  by  an  elongated 
interval ;  one,  narrow,  from  the  upper  bone  of  the  sternum  • 
the  other,  broader,  from  the  sternal  third  of  the  clavicle ; 
the  extent  of  the  clavicular  attachment  varies,  and  in  some 
bodies  may  reach  even  to  the  trapezius  muscle.  These  two 
heads  unite  at  about  the  middle  of  the  neck  in  a  rounded 
belly,  which  is  inserted  into  the  mastoid  process,  and  by  a 
broad  and  thin  aponeurosis  into  the  superior  curved  line  of 
the  occipital  bone. 

The  OMO-HYOID  MUSCLE  is  a  small  muscle  which  traverses 
the  neck  diagonally,  in  a  direction  crossing  that  of  the 
sterno-mastoid,  beneath  which  it  lies;  it  is  composed  of 
two  bellies,  united  in  the  middle  b}^  a  tendon  of  variable 
length ;  only  one  portion  of  the  muscle  can  be  well  seen 
in  the  present  stage  of  the  dissection.  It  arises  from  the 
scapula  at  the  outside  of,  and  sometimes  in  part  from,  the 
transverse  ligament  stretching  across  the  supra-scapular 
notch ;  it  then  passes  forward,  obscured  from  sight  by  the 
clavicle;  behind  the  sterno-mastoid,  the  scapular  portion 
terminates  in  a  tendon  which  plays  through  a  loop  formed 
by  the  deep  cervical  fascia,  this  loop  being  attached  to  the 
cartilage  of  the  first  rib.  From  this  intervening  tendon 
commences  another  belly,  which  pursues  a  direction  up- 
•ward  and  forward,  to  be  inserted  into  the  hyoid  bone  at 
the  point  of  union  between  its  body  and  the  greater  cornu. 
Occasionally-,  one  of  the  bellies  of  this  muscle  is  wanting, 
and  the  whole  muscle  may  be  absent. 

The  sterno-mastoid  and  the  omo-hyoid  muscles  divide  the 
quadrilateral  cervical  region  into  "  triangles,"  con venient  for 


SUPERFICIAL    CERVICAL    REGION.  41 

purposes  of  surgical  description  ;  thus,  the  sterno-mastoid 
passing  obliquely  across  the  neck,  that  portion  bounded  by 
the  median  line  in  front,  the  jaw  above  and  the  sterno- 
mastoid  behind,  is  called  the  great  anterior  triangle;  that 
bounded  by  the  sterno-mastoid  in  front,  the  clavicle  below 
and  the  trapezius  posteriorly,  the  great  posterior  triangle. 
These  triangles  are  each  subdivided  by  the  omo-hyoid 
muscle;  the  hyoid  portion  divides  the  anterior  triangle,  the 
space  below  it  being  called  the  inferior  carotid  triangle; 
that  above  it  being  again  divided  by  the  digastricus  muscle 
into  the  superior  carotid  triangle  and  the  submaxillary  tri- 
angle. The  scapular  portion  divides  the  posterior  triangle 
into  two  smaller  spaces,  that  above  the  belly  of  the  muscle 
being  called  the  occipital  triangle  and  that  below  it  the 
subclavian  triangle. 

The  sterno-mastoid  muscle  may  now  be  divided  and  its  two  ends 
reflected. 

In  reflecting  the  lower  half  of  the  sterno-mastoid  muscle, 
its  outer  border  will  be  seen  to  correspond  with  the  outer 
border  of  the  scalenus  anticus  muscle.  As  the  position  of 
the  last-named  muscle  at  its  insertion  to  the  first  rib  is  of 
importance  in  connection  with  the  operation  of  ligature 
of  the  subclavian  arteiy,  this  relation  is  a  valuable  land- 
mark to  recognize. 

In  reflecting  the  upper  half  of  the  sterno-mastoid  muscle, 
its  posterior  surface  should  be  examined  for  the  spinal 
accessory  nerve;  this  nerve  is  one  of  the  eighth  pair  of 
cranial  nerves  (p.  37);  after  emerging  from  the  foramen 
lacerum  posterius,  it  becomes  connected  by  a  branch  of 
considerable  size  with  the  pneumogastric  nerve,  and  then 
continues  onward  to  perforate  the  sterno-mastoid  muscle  at 
its  under  surface,  after,  passing  through  which,  and  being 
joined  by  branches  of  the  cervical  plexus  in  the  occipital 
triangle,  it  is  distributed  to  the  trapezius  muscle. 

It  is  presumed  that  the  carotid  artery  has  not  yet  been 
exposed,  but  that  it  still  remains  covered  with  its  sheath. 
Its  sheath  is  a  portion  of  the  deep  cervical  fascia  which 
invests  it  and  also  the  internal  jugular  vein.  Upon  this 
sheath  may  be  seen  a  small  nerve  called  the  descendens 
noni;  it  is  a  branch  from  the  hypoglossal,  one  of  the  cra- 
nial nerves,  which  crosses  the  neck  in  a  transverse  direc- 
tion just  above  the  hyoid  bone.  The  descendens  noni  forms 
a  loop  with  a  deep  branch  from  the  second  or  third  nerve 

4* 


42  ANATOMY    OF    THE    HEAD    AND    NECK. 

of  the  cervical  plexus,  called  the  communicans  noni.  The 
descendens  noni  is  sometimes  found  within  the  sheath 
instead  of  upon  it. 

Upon  opening  the  carotid  sheath,  the  relation  of  the 
parts  is  to  be  carefully  observed.  The  artery  and  vein  are 
separated  from  each  other  by  a  thin  septum  derived  from 
the  sheath.  The  vein  is  the  internal  jugular  vein,  and  lies 
upon  the  outer  side  of  the  artery.  Behind  and  between 
the  artery  and  vein  will  be  found  the  pneumogastric  or  par 
vagum  nerve.  Upon  the  inside  of  the  artery  the  trachea 
will  be  seen,  and  between  the  trachea  and  artery  a  medium- 
sized  nerve  destined  to  the  larynx,  and  called  the  recurrent 
laryngeal.  Between  the  artery  and  the  transverse  processes 
of  the  cervical  vertebrae,  on  which  it  rests,  may  be  found 
that  part  of  the  sympathetic  nerve  which  connects  the 
cervical  ganglia.  Some  small  branches  of  the  sj'mpathetic 
nerve,  being  cardiac  branches,  should  also  be  noticed  in 
connection  with  this  view  of  the  parts. 

The  common  carotid  artery  is  of  large  size  and  uniform 
calibre,  and  from  its  origin  until  its  division  opposite  the 
upper  border,  of  the  thyroid  cartilage,  gives  off  no  branch 
unless  it  be  a  small  muscular  twig.  Its  course  is  indicated 
by  a  line  drawn  from  the  centre  of  the  interval  between  the 
mastoid  process  and  the  angle  of  the  jaw  to  the  steruo- 
clavicular  articulation ;  this  line  corresponds  to  the  ante- 
rior border  of  the  sterno-mastoid  muscle,  which  is  called  the 
guide  to,  or  the  satellite  of,  the  artery.  At  the  apex  of  the 
triangle  formed  by  the  anterior  belly  of  the  omo-hyoid  and 
the  anterior  border  of  the  sterno-mastoid  muscles  is  the 
u  point  of  election"  for  placing  a  ligature  upon  the  common 
carotid  artery. 

Having  established  these  various  relations,  the  dissection 
may  be  continued  by  the  examination  of  the  muscles  lying 
upon  the  trachea. 

The  STERNO-HYOID  MUSCLE  lies  at  the  side  of  the  median 
line  of  the  neck,  being  covered  in  at  its  lower  part  by  the 
sterno-mastoid,  and  is  a  thin  ribbon-like  muscle  about  an 
inch  in  width,  separated  from  its  fellow  of  the  other  side 
by  a  slight  cellular  interval.  It  arises  from  the  internal 
surface  of  the  first  bone  of  the  sternum  by  a  flat  muscular 
origin,  and  is  inserted  into  the  lower  border  of  the  body 
of  the  hyoid  bone.  It  is  occasionally  marked  by  trans- 
verse tendinous  intersections.  It  lies  upon  the  stern o- 
thyroid  and  thyro-hyoid  muscles. 


SUPERFICIAL    CERVICAL    REGION.  43 

The  sterno-hyoid  is  to  be  divided  and  its  two  ends  are  to  be  re- 
flected. In  separating  the  steruo-hyoid  and  the  thyro-hyoid  muscles 
on  the  median  line  the  student  should  observe  their  relations  with  the 
trachea  and  the  isthmus  of  the  thyroid  gland,  these  being  parts  con- 
cerned in  the  operation  of  tracheotomy. 

The  STERNO-THYROID  MUSCLE  arises  also  from  the  tho- 
racic surface  of  the  first  bone  of  the  sternum,  but  lower 
down  than  the  preceding  muscle:  it  is  inserted  into  the 
oblique  line  of  the  thyroid  cartilage  of  the  larynx  ;  it  is 
broader  than  the  stern o-li}7oid,  and,  like  that,  is  occasionally 
marked  by  tendinous  intersections. 

The  THYRO-HYOID  MUSCLE  is  a  short  muscle  arising  from 
the  oblique  line  of  the  thyroid  cartilage  and  inserted  into 
the  lower  border  of  the  body  and  cormi  of  the  hyoid  bone. 
The  separation  between  this  muscle  and  the  sterno-thyroid 
is  not  always  distinct ;  normally  they  are  separated  by  a 
tendinous  interval  at  the  point  where  they  are  attached  to 
the  oblique  line  of  the  thyroid  cartilage,  but  it  not  unfre- 
quently  happens  that  even  this  is  not  sufficiently  marked 
to  be  apparent. 

The  sterno-thyroid  muscle  is  to  be  divided,  and  its  ends  reflected, 
so  as  to  expose  the  thyroid  body. 

Between  the  common  carotid  arteries  and  upon  the  tra- 
chea lies  the  THYROID  BODY  ;  this  is  a  dark  red  and  vascu- 
lar organ  composed  of  two  lobes,  one  on  each  side  of  the 
trachea  and  larynx,  connected  by  a  narrow  portion  called 
the  isthmus,  and  which  lies  across  the  upper  two  or  three 
rings  of  the  trachea  ;  the  lobes  are  triangular  in  shape,  their 
bases  being  directed  downward.  It  is  well  supplied  with 
arteries,  receiving  one  from  each  external  carotid,  called 
the  superior  thyroid,  distributed  to  the  upper  part  of  the 
lobes,  and  one  from  each  thyroid  axis  of  the  subclavian, 
called  the  inferior  thyroid,  which  supplies  the  lower  part 
of  the  lobes  ;  occasionally  there  is  a  middle  thyroid  artery 
sent  to  it  from  the  arteria  innominata ;  all  these  arteries 
anastomose  freely  with  each  other.  When  the  middle  thy- 
roid is  present,  it  usually  lies  upon  the  trachea  in  the  me- 
dian line,  and  may  be  a  source  of  embarrassment  in  the 
operation  of  tracheotomy.  A  small  muscle  called  the  leva- 
tor  glandulse  thyroidese  is  sometimes  found  connected  with 
the  upper  border  of  one  lobe  or  with  the  isthmus,  and 
attached  to  the  hyoid  bone ;  it  is  said  to  be  most  frequent 
on  the  left  side,  and  its  place  is  sometimes  supplied  by  a 
small  lobule  of  glandular  tissue,  which  is  then  called  the 
pyramid,  or  middle  lobe. 


44  ANATOMY    OF    THE     HEAD    AND     NECK. 

DISSECTION  VI. 

EXTERNAL  CAROTID  ARTERY. 

The  dissection  of  the  external  carotid  artery  is  to  be  undertaken 
by  following  out  from  the  main  trunk  those  branches  which  have 
been  partly  dissected,  in  preparing  the  parts  already  examined,  as 
well  as  those  which  have  not  yet  been  alluded  to,  but  are  now  to  be 
described. 

Opposite  the  upper  border  of  the  thyroid  cartilage  or  a 
little  higher,  the  common  carotid  artery  divides  into  two 
large  trunks,  the  external  and  internal  carotid  branches. 
At  first,  the  external  carotid  lies  upon  the  inner  side, 
nearer  the  middle  line  of  the  body  than  the  internal 
carotid,  their  distinctive  names  having  reference,  not  to 
their  relative  position,  but  to  their  destination  to  parts 
nearer  or  more  remote  from  the  surface  ;  it  soon,  however, 
becomes  superficial  to  the  internal  carotid  and  divides  into 
numerous  branches.  The  internal  caroiid  may  be  distin- 
guished b}T  a  peculiar  fusiform  dilatation  at  its  commence- 
ment ;  sometimes  this  dilatation  is  very  marked,  forming 
an  abrupt  rounded  distension  of  the  vessel. 

The  external  carotid  is  crossed  by  the  stylo-hyoid  and 
digastricus  muscles,  and  by  the  hypoglossal  nerve,  and  is 
imbedded  for  a  part  of  its  course  in  the  parotid  gland  ; 
between  the  angle  of  the  jaw  and  the  mastoid  process  it 
terminates  by  dividing  into  the  internal  maxillary  and 
temporal  arteries.  Its  branches  are  the 

Superior  thyroid,  Posterior  auricular, 

Lingual,  Ascending  pharyngeal, 

Facial,  Temporal, 

Occipital,  Internal  maxillary. 

The  superior  thyroid  artery  descends,  passing  beneath  the  omo-hyoid, 
sterno-thyroid,  and  sterno-hyoid  muscles  to  the  thyroid  body,  to  the 
superficial  surface  of  which  it  is  distributed,  and  where  it  anastomoses 
with  its  fellow  of  the  opposite  side.  It  sends  offsets  to  the  hyoid  region 
and  larynx,  under  the  name  of  superior  hyoid  and  inferior  larynyeal 
branches. 

The  lingual  artery  passes  obliquely  forward  beneath  the  hyo-glossus 
muscle.  In  that  part  of  its  course  which  is  parallel  to  the  os  hyoides, 
the  hyo-glbssus  muscle  separates  it  from  the  hypoglossal  nerve,  the 
latter  being  the  more  superficial.  The  lingual  artery  supplies  the 
tongue,  and  is  continued  forward  to  the  tip  of  that  organ  under  the 
name  of  the  ranine  artery. 

The  facial  artery  arises  above  the  lingual,  sometimes  from  a  com- 


EXTERNAL    CAROTID    ARTERY.  45 

raon  trunk  with  it,  and  is  directed  upward  over  the  lower  jaw  to  the 
face.  It  passes  beneath  the  digastric  and  stylo-hyoid  muscles  and 
becomes  imbedded  in  the  snbmaxillary  gland.  In  its  cervical  por- 
tion it  gives  branches  to  the  pharynx,  tonsils,  and  submaxillary  gland. 
The  submenfal  branch  arises  from  the  portion  within  the  gland,  and 
passes  forward  upon  the  mylo-hyoideus  muscle  to  the  anterior  belly 
of  the  digastricus,  where  it  terminates  in  branches,  some  of  which 
turn  upward  and  reach  nearly  to  the  lower  lip.  Before  crossing  the 
jaw,  which  it  does  close  to  the  anterior  inferior  angle  of  the  masseter 
muscle,  the  facial  artery  is  tortuous,  and  continues  so  throughout  the 
rest  of  its  course  (p.  22). 

The  occipital  artery  is  a  lai'ge  branch  destined  to  the  posterior  part 
of  the  head  ;  it  passes  outward  beneath  the  posterior  belly  of  the 
digastricus,  part  of  the  parotid  gland,  the  sterno-mastoid  and  trapezius 
muscles  ;  it  crosses  the  jugular  vein  and  the  spinal  accessory  nerve, 
and  the  hypoglossal  nerve  curves  around  it  near  its  origin.  Near  the 
middle  line  of  the  occipital  bone  the  artery  turns  upward,  passing 
through  the  fibres  of  the  upper  part  of  the  trapezius  muscle,  becomes 
superficial,  and  is  distributed  to  the  occiput,  anastomosing  with  its 
fellow,  with  the  posterior  auricular  and  with  the  temporal  arteries. 
It  gives  off  a  small  branch,  the  inferior  meningeal,  which  ascends  with 
the  jugular  vein  through  the  foramen  lacerum  posterius  to  the  pos- 
terior fossa  of  the  base  of  the  skull.  A  large  but  irregular  branch, 
the  princeps  cerricis,  descends  the  neck  between  the  complexus  and 
seini-spinalis  colli  muscles  and  inosculates  with  the  profunda  cervicis, 
a  branch  of  the  subclavian  artery. 

The  posterior  auricular  artery  ascends  between  the  ear  and  the 
occipital  bone,  and  is  distributed  by  two  branches  to  the  external  ear 
and  side  of  the  head.  It  sends  a  small  twig,  called  the  stijfo-mastoid, 
through  the  stylo-mastoid  foramen  to  the  internal  ear.  This  artery 
is  sometimes  an  offset  from  the  occipital. 

The  ascending  pharyngeal.  artery  arises  at  the  point  of  bifurcation  of 
the  common  carotid,  and  is  very  apt  to  be  destroyed  in  the  dissection. 
It  is  of  small  size,  and  ascends  between  the  internal  carotid  and  the 
pharynx.  It  divides  into  two  branches,  the  inferior  meninqeal,  which 
enters  the  cranium  through  the  foramen  lacerum  posterius,  and  is 
distributed  to  the  membranes  of  the  posterior  fossa  of  the  skull,  and 
the  pharyngeal,  which  is  distributed  to  the  mucous  membrane  of  the 
pharynx  and  the  soft  palate. 

The  temporal  artery  is  the  terminal  continuation  of  the  external 
carotid  ;  it  passes  up  between  the  ear  and  the  articulation  of  the 
jaw,  through  the  substance  of  the  parotid,  and  upon  the  temporal 
fascia  divides  into  two  branches,  anterior  and  posterior  temporal, 
which  ramify  on  the  front  and  the  side  of  the  head.  This  artery 
gives  off  parotidean  branches  to  the  parotid  gland  ;  the  anterior  auricu- 
lar to  the  external  ear  ;  the  transverse  facial  to  the  muscles  of  the  face, 
crossing  the  cheek  transversely  beside  Steno's  duct,  and  anastomosing 
with  branches  of  the  facial  (p.  23)  ;  the  ornitar  to  anastomose  with  the 
palpebral  arteries,  and  the  middle  temporal,  which  perforates  the  tem- 
poral fascia  just  above  the  zvsoma,  and  supplies  the  temporal  muscle. 

The  internal  maxillary  will  be  described  hereafter. 


46  ANATOMY     OP     THEIIEAD     AND     NECK. 


SUBMAXILLARY   REGION. 

The  dissection  of  the  carotid  artery  will  have  exposed 
and  prepared  a  number  of  parts  situated  below  the  in- 
ferior maxillary  bone  and  between  it  and  the  hyoid  bone. 

The  DIGASTRICUS  MUSCLE,  lying  above  the  hyoid  bone  and 
connected  with  it,  is  composed  of  two  rounded  bellies  con- 
nected by  a  central  tendon,  the  central  tendon  being  the 
part  attached  to  the  hyoid  bone  ;  these  two  bellies  form  an 
obtuse  angle  with  each  other ;  the  posterior  one  arises  from 
the  digastric  fossa  of  the  temporal  bone  and  is  consequently 
covered  in  by  the  mastoid  portion  of  the  sterno-mastoid 
muscle  and  by  the  parotid  gland.  The  anterior  belly, 
closely  connected,  though  not  united  with  the  correspond- 
ing part  of  the  same  muscle  on  the  other  side  of  the  neck, 
arises  from  the  side  of  the  symphysis  of  the  lower  jaw  ; 
these  two  portions  are  attached  by  their  central  tendon  to 
the  body  and  greater  cornu  of  the  os  hyoides.  The  tendon 
of  the  muscle  is  held  in  its  place  by  a  strong  fascia  and  by 
fibres  of  the  stylo-hyoid  muscle  which  surround  it.  The 
posterior  belly  of  this  muscle  crosses  the  carotid  vessels, 
and  along  its  lower  border  will  be  found  the  occipital 
artery  and  the  hypoglossal  nerve.  The  facial  nerve  sends 
a  branch  to  this  muscle  soon  after  its  exit  from  the  stylo- 
mastoid  foramen. 

The  STYLO-HYOID  MUSCLE  is  in  close  connection  with  the 
preceding ;  it  arises  from  the  styloid  process  of  the  tem- 
poral bone,  and  passes  down  behind  and  to  the  inner  side 
of  the  posterior  belly  of  the  digastricus ;  at  its  lower  part 
it  splits,  and  allows  the  digastric  tendon  to  pass  through 
its  substance ;  it  is  inserted  into  the  os  hyoides  at  the  union 
of  its  body  and  cornu.  It  is  sometimes  wanting.  The 
facial  nerve  sends  a  branch  to  this  muscle  also,  soon  after 
it  emerges  from  its  foramen. 

The  anterior  belly  of  the  digastricus  is  to  be  removed,  and  the  sub- 
maxillary  gland  freed  from  extraneous  cellular  tissue,  and  loosened 
from  its  attachments. 

The  SUBMAXILLARY  GLAND  is  a  salivary  gland,  next  in 
size  to  the  parotid,  which  it  resembles  in  general  structure; 
it  lies  above  the  digastricus  and  upon  the  mylo-hyoicl 
muscle ;  it  is  partly  concealed  by  the  lower  jaw,  though  it 
descends  a  variable  distance  down  the  neck ;  it  is  traversed 
by  the  facial  artery,  which  distributes  numerous  small 


SUB  MAXILLARY    REGION.  47 

branches  throughout  its  substance ;  its  duct,  called  Wh.ar- 
torfs  duct,  may  be  seen  issuing  from  its  posterior  part,  and 
curving  around  the  posterior  border  of  the  mylo-hyoid 
muscle,  passes  between  the  hyo-glossus  and  genio-hyo- 
glossus  muscles  and  beneath  the  sublingual  gland,  to  open 
at  the  side  of  the  frenum  of  the  tongue. 

The  MYLO-HYOID  MUSCLE  arises  from  the  mylo-hyoid  ridge 
of  the  inferior  maxillary  bone,  and  its  posterior  fibres  pass 
forward  to  be  inserted  into  the  body  of  the  os  hyoides; 
the  anterior  fibres  join  with  those  of  the  muscle  of  the 
other  side,  forming  a  sort  of  raphe  along  the  median  line  ; 
it  is  triangular  in  shape,  and  with  its  fellow  makes  the 
floor  of  the  mouth,  the  two  muscles  stretching  across  the 
interval  between  the  two  sides  of  the  lower  jaw.  The 
mylo-hyoid  branch  of  the  inferior  dental  nerve  ramifies 
upon  its  cutaneous  surface,  as  well  as  a  twig  from  the  in- 
ternal maxillary  artery,  which  accompanies  that  nerve. 
The  submental  branch  of  the  facial  artery  also  ramifies 
upon  this  muscle. 

The  mylo-hyoid  muscle  is  to  be  carefully  removed  or  turned  down 
toward  the  hyoid  bone. 

The  GTENIO-HYOID  MUSCLE  lies  close  to  the  median  line, 
and  arises  from  the  inside  of  the  symphysis  of  the  lower 
jaw ;  it  is  inserted  into  the  centre  of  the  body  of  the  hyoid 
bone,  in  close  apposition  with  the  muscle  of  the  other  side, 
with  which  it  is  often  united. 

The  hyo-glossus  and  genio-hyo-glossus  will  be  found  described  in 
connection  with  the  tongue. 

If  the  snbmaxillary  gland  has  been  preserved,  Wharton's 
duct  may  be  seen  resting  upon  the  hyo-glossus  muscle. 
The  hypoglossal  nerve  crosses  that  muscle,  and  in  this 
part  of  its  course  gives  off  the  descendens  noni  branch 
to  the  sheath  of  the  carotid  vessels  (p.  41).  By  drawing 
the  os  hyoides  downward  the  gustatory  branch  of  the  in- 
ferior maxillary  nerve  will  also  be  found  resting  upon  the 
hyo-glossus  muscle.  The  submaxillary  ganglion,  a  small 
reddish  body,  is  in  close  connection  with  the  gustatory 
nerve,  and  lies  just  above  the  upper  border  of  the  sub- 
maxillary  gland;  it  is  extremely  difficult  to  find.  The 
chorda,  tympani,  a  branch  of  the  facial  nerve  which  joins 
the  gustatory  nerve  near  the  submaxillary  ganglion,  may 
also  be  seen  at  this  point  of  the  dissection. 


48  ANATOMY    OF    THE    HEAD    AND    NECK. 

DISSECTION  VII. 

PTERYGO-MAXILLARY   REGION. 

The  parts  beneath  the  ramus  of  the  jaw  are  of  difficult  dissection  ; 
and  the  numerous  important  structures  crowded  into  this  space,  are 
only  by  patience  eliminated  from  their  apparent  confusion,  or  pre- 
served in  sufficient  integrity  to  permit  their  examination.  The 
zygoma  having  been  already  divided  at  its  two  ends,  and,  with  the 
masseter,  turned  downward,  the  next  step  is  to  saw  through  the 
inferior  maxillary  bone  below  its  neck,  and  again  from  the  last  molar 
tooth  to  just  below  its  angle  ;  this  fragment,  with  the  temporal  muscle 
attached  to  the  coronoid  process,  is  then  to  be  turned  outward,  and 
both  in  reflecting  it,  and  in  sawing  it  through,  the  greatest  caution  is 
to  be  observed  to  divide  nothing  accidentally  upon  the  inside  of  the 
bone,  the  internal  maxillary  artery  and  the  inferior  dental  artery  and 
nerve  being  in  close  apposition  to  it.  After  this  piece  of  bone  has 
been  everted,  and  a  little  cellular  tissue  cleared  away,  the  pterygoid 
muscles  will  appear,  the  external  directed  toward  the  condyle  of  the 
jaw,  and  the  internal  toward  its  angle.  The  coronoid  process  should 
be  examined,  to  see  the  extent  to  which  the  temporal  muscle  is 
attached  to  its  inner  surface  (p.  26). 

THE  EXTERNAL  PTERYGOID  MUSCLE  arises  by  two  heads 
from  the  greater  wing  of  the  sphenoid  bone,  below  the 
crest,  and  from  the  outer  surface  of  the  external  pterygoid 
plate ;  its  fibres  converge  to  be  inserted  in  front  of  the  neck 
of  the  inferior  maxilla ;  its  separation  into  two  heads  is  not 
always  apparent ;  when  present,  the  second  head  is  inserted 
into  the  inter-articular  nbro-cartilage  of  the  ternporo-max- 
illary  articulation.  The  internal  maxillary  artery  rests  upon 
this  muscle. 

The  INTERNAL  PTERYGOID  MUSCLE  arises  from  the  ptery- 
goid fossa  and  from  the  inner  surface  of  the  external 
pterygoid  plate,  and  is  inserted  into  the  angle  and  inner 
surface  of  the  ramus  of  the  lower  jaw;  its  fibres  follow  the 
same  direction  as  those  of  the  masseter  muscle  externally, 
and  from  this  fact,  as  well  as  from  the  correspondence  of 
their  insertions,  it  has  sometimes  been  called  the  internal 
masseter  .muscle. 

ARTICULATION  OF  THE  LOWER  JAW. 

In  the  TEMPORO-MAXILLARY  ARTICULATION  the  condyle 
of  the  lower  jaw  is  received  into  the  glenoid  fossa  of  the 
temporal  bone,  and  is  held  in  place  by  three  ligaments. 

The  external  lateral  ligament  is  a  short,  stout  band  of 


ARTICULATION     OF    THE    LOWER    JAW.  49 

fibres,  passing  obliquely  backward  from  the  tubercle  of  the 
zygoma  to  the  outer  side  of  the  neck  of  the  lower  jaw. 

The  internal  lateral  ligament  is  a  membranous  expansion 
from  the  spinous  process  of  the  sphenoid  bone  to  the  mar- 
gin of  the  dental  foramen ;  the  internal  maxillary  artery 
and  dental  nerve  pass  between  this  ligament  and  the  jaw. 

The  stylo-maxillary  ligament  extends  from  the  styloid 
process  of  the  temporal  bone  to  the  inside  of  the  angle  of 
the  jaw. 

These  two  latter  hardly  merit  the  name  of  ligaments,  as 
they  in  no  way  serve  to  consolidate  the  articulation ;  the 
first  being  but  a  membranous  protection  to  the  vessels,  and 
the  second  an  aponeurotic  surface  of  origin  of  the  stylo- 
glossus  muscle. 

An  inter-articular  fibro-cartilage  is  seen  on  opening  the 
joint;  it  is  elliptical  and  biconcave  in  shape,  and  sometimes 
perforated  in  the  centre :  externally  it  is  attached  to  the 
external  lateral  ligament,  and  internally  to  the  external 
pterygoid  muscle. 

Two  synovial  membranes  are  present,  forming  a  shut  sac 
above  and  below  the  inter-articular  cartilage. 

The  condyle  of  the  jaw,  with  the  external  pterygoid  muscle  at- 
tached, is  now  to  be  dislocated  and  drawn  forward. 

The  superior  and  inferior  maxillary  trunks  of  the  fifth 
pair  of  cranial  nerves  will  then  be  seen  issuing  from  the 
skull ;  the  former  by  the  foramen  rotundum,  and  crossing 
the  spheno-maxillary  fossa  to  the  canal  in  the  floor  of  the 
orbit  (p.  35) ;  the  latter  by  the  foramen  ovale,  and  dividing 
into  two  branches;  the  anterior  giving  off  five  muscular 
branches  to  the  masseter,  buccinator,  temporal,  and  exter- 
nal and  internal  pterygoid  muscles ;  the  posterior  dividing 
into  the  auriculo-temporal,  inferior  dental,  and  gustatory 
branches  (p.  35).  A  branch  from  the  internal  maxillary 
artery  accompanies  each  of  the  nerves  sent  to  the  above- 
named  muscles.  The  otic,  or  Arnold's  ganglion,  should  be 
sought  for,  resting  upon  the  inner  surface  of  the  inferior 
maxillary  nerve,  just  below  the  foramen  ovale. 

The  auriculo-temporal  nerve,  the  terminal  branches  of 
which  have  been  already  dissected  (p.  24),  separates  from 
the  inferior  maxillary  near  the  skull;  it  passes  outward 
beneath  the  external  pterygoid  muscle  to  the  inner  side  of 
the  articulation  of  the  jaw,  from  which  point  it  ascends 
5 


50  ANATOMY    OF    THE     HEAD    AND    NECK. 

with  the  temporal  artery  to  ramify  externally  upon  the 
side  of  the  head. 

The  inferior  dental  nerve  is  the  largest  of  the  three 
branches  into  which  the  posterior  trunk  of  the  inferior 
•maxillary  divides ;  it  lies  at  first  beneath  the  external 
pterygoid  muscle;  afterward  upon  the  internal  pterygoid; 
it  then  enters  the  inferior  maxillary  bone  at  the  inferior 
dental  foramen,  to  emerge  at  the  mental  foramen  (p.  22), 
and  supply  the  lower  lip  and  chin  ;  this  nerve  is  accompa- 
nied by  the  inferior  dental  branch  of  the  internal  maxillary 
artery.  Before  entering  the  canal  in  the  bone,  the  inferior 
dental  nerve  gives  off  the  mylo-hyoid  branch,  which,  accom- 
panied by  the  mylo-hyoid  artery,  a  twig  from  the  inferior 
dental,  is  continued  along  the  inner  aspect  of  the  jaw  to 
the  mylo-hyoid  muscle. 

The  gustatory  nerve  descends  between  the  two  pterygoid 
muscles  to  the  side  of  the  tongue,  to  the  mucous  membrane 
of  which  it  is  distributed;  its  final  distribution  will  be 
described  with  the  dissection  of  the  tongue.  The  small 
chorda  tympani  branch  of  the  facial  nerve,  arising  within 
the  temporal  bone,  and  emerging  from  an  aperture  near 
the  fissura  Glaseri,  joins  the  gustatory  nerve,  and,  passing 
down  in  close  apposition  with  it,  establishes  a  connection 
with  the  submaxillary  ganglion. 

The  internal  maxillary  artery,  one  of  the  terminal 
branches  of  the  external  carotid,  passes  inward  behind  the 
neck  of  the  lower  jaw,  over  the  external  pterygoid  muscle, 
to  the  spheno-maxillary  fossa ;  it  is  very  tortuous,  and 
sends  off  a  large  number  of  small  branches;  these  are  the 

Masseteric,  Inferior  dental,  Infra-orbital, 

Buccal,  Tympanic,  Ptery  go-palatine, 

Temporal  (deep),  Meningea  media,  Spheno-palatine, 

External  pterygoid,  Meningea  parva,  Posterior  palatine, 

Internal  pterygoid,  Superior  dental,  Vidian. 

The  five  muscular  branches,  the  first  named  of  the  above  list,  and 
the  inferior  dental,  have  been  seen  in  connection  with  corresponding 
branches  of  the  anterior  trunk  of  the  inferior  maxillary  and  the  infe- 
rior dental  nerves.  These  branches  are  all  capable  of  demonstration. 

The  meningea  media  branch  ascends  beneath  the  external  pterygoid 
muscle,  and  enters  the  skull  through  the  foramen  spinosum  of  the  sphe- 
noid bone,  to  be  distributed  to  the  middle  fossa  of  the  cranial  cavity. 

The  meningea  parva  branch  passes  through  the  foramen  ovale,  the 
same  at  which  the  inferior  maxillary  nerve  emerges,  and  is  also  dis- 
tributed to  the  middle  fossa  of  the  skull. 

The  superior  dental  branch,  deeper  seated  than  those  already  de- 
scribed, descends  in  a  tortuous  manner  upon  the  tuberosity  of  the 


DEEP    CERVICAL    REGION.  51 

superior  maxillary  bone,  sending  branches  through  small  foramina  to 
the  teeth,  the  antrum,  and  the  mucous  membrane  of  the  gums. 

The  infra-orbital  branch  is  the  terminal  portion  of  the  internal  maxil- 
lary artery ;  from  the  spheno-maxillary  fossa  it  enters  the  infra-orbital 
canal  with  the  superior  maxillary  nerve,  and  emerges  on  the  face  at 
the  infra-orbital  foramen  (p.  19). 

The  remaining  branches  of  the  internal  maxillary  artery  are  of  very 
small  size,  and,  like  the  branches  of  the  superior  maxillary  nerve, 
which  they  accompany,  are  incapable  of  demonstration,  except  by  a 
special  dissection. 

The  internal  maxillary  vein  receives  the  veins  corre- 
sponding to  the  branches  of  the  artery,  and  unites  with 
the  temporal  vein  in  a  trunk,  called  the  temporo-maxillary, 
which  is  one  of  the  principal  in  forming  the  external  jugu- 
lar vein ;  the  veins  of  the  region  form  a  plexus  between  the 
two  pterygoid  muscles. 

The  STYLO-GLOSSUS  MUSCLE  will  be  found,  as  its  name 
implies,  arising  from  the  apex  of  the  styloid  process  of  the 
temporal  bone ;  it  is  crossed  by  the  gustatory  nerve,  and 
is  inserted  into  the  side  of  the  tongue. 

The  STYLO-PHARYNGEUS  MUSCLE  lies  below  the  preced- 
ing ;  it  arises  from  the  base  of  the  styloid  process,  and  is 
inserted  into  the  pharynx  and  upper  border  of  the  thyroid 
cartilage ;  it  passes  between  the  external  and  internal  caro- 
tid arteries,  and  the  glosso-pharyngeal  nerve  turns  over 
the  lower  part  of  its  fleshy  belly. 

Between  the  stylo-glossus  and  stylo-pharyngeus  muscles 
is  a  fibrous  band,  connecting  the  tip  of  the  styloid  process 
with  the  lesser  cornu  of  the  os  hyoides ;  it  is  called  the 
stylo-hyoid  ligament,  and  is  sometimes  cartilaginous,  or 
even  osseous,  in  a  part  or  the  whole  of  its  extent. 

The  styloid  process  is  now  to  be  cut  through  at  its  base,  and  with 
the  two  muscles  just  described  turned  downward  ;  the  fascia  surround- 
ing the  internal  carotid  artery  and  the  internal  jugular  vein  is  to  be 
removed  without  disturbing  the  nerves  in  the  vicinity  of  those  ves- 
sels ;  they  are  the  pneumogastric,  glosso-pharyngeal,  hypoglossal, 
sympathetic,  and  spinal  accessory. 

DEEP   CERVICAL   REGION. 

THE  INTERNAL  JUGULAR  VEIN  is  in  close  connection  with, 
and  lies  upon  the  outer  side  of,  the  internal  carotid  artery'; 
it  emerges  from  the  skull  at  the  foramen  jugulare,  as  the 
continuation  of  the  lateral  and  petrosal  sinuses  ;  at  about 
the  level  of  the  os  hyoides  its  size  is  considerably  increased 
by  the  junction  with  it  of  the  facial,  lingual,  thyroid,  and 
occipital  veins.  Between  the  skull  and  h}'oid  bone,  this 


52  ANATOMY    OP    THE     HEAD    AND    NECK. 

vein  is  sometimes  called  the  internal  cephalic,  and  below 
that  point  the  internal  jugular.  Below  the  hyoid  bone,  it 
passes  downward,  parallel  with  and  to  the  outer  side  of  the 
common  carotid  artery,  to  join  the  subclavian  vein,  and  with 
that  forms  the  vena  imiominata.  At  the  lower  part  of  the 
neck  its  position  corresponds  to  the  interval  between  the 
sternal  and  clavicular  attachments  of  the  sterno-mastoid 
muscle. 

The  PNEUMOGASTRIC  NERVE  emerges  from  the  jugular 
foramen,  and  will  be  recognized  by  the  ganglion  (ganglion  of 
the  trunk)  peculiar  to  it;  this  is  nearly  an  inch  in  length,  and 
is  surrounded  by  small  nerves.  The  nerve  lies  between  the 
jugular  vein  and  internal  carotid  artery,  and  communicates 
with  the  hypoglossal,  spinal  accessory,  and  sympathetic 
nerves ;  it  distributes  branches  to  the  parts  about  it,  giving 
off  a  pharyngeal  branch  which  unites  with  the  glosso- 
pharyngeal  nerve,  and  with  which  it  forms  a  plexus  on  the 
pharynx;  the  superior  laryngeal  branch,  of  considerable 
size,  passes  inside  the  internal  carotid  artery  to  the  larynx, 
which  it  enters  between  the  hyoid  bone  and  thyroid  carti- 
lage, perforating  the  thyro-hyoid  membrane,  and  supplies 
the  crico-thyroid  muscle  ;  it  also  gives  off  cardiac  branches, 
which  unite  with  those  of  the  sympathetic. 

The  GLOSSO-PHARYNGEAL  NERVE  also  escapes  from  the 
jugular  foramen,  and  should  be  traced  up  to  its  ganglion, 
the  ganglion  petrosum  or  ganglion  of  Andersch,  which  lies 
close  to  the  bone,  and  from  which  emanate  the  branches 
which  unite  it  with  the  other  nerves  of  this  region.  This 
nerve  crosses  over  the  internal  carotid  to  the  lower  border 
of  the  stylo-pharyngeus  muscle ;  it  there  assumes  an  almost 
transverse  direction  to  the  pharynx,  and  finally  passes 
under  the  hyo-glossus  muscle,  to  be  distributed  to  the  pha- 
rynx, tongue,  and  tonsil. 

The  SPINAL  ACCESSORY  NERVE,  blending  with  the  trunk 
of  the  pneumogastric,  issues  from  the  foramen  jugulare, 
and  is  connected  by  small  branches  with  the  other  nerves 
of  this  region.  It  passes  outward,  either  over  or  under  the 
jugular  vein,  to  perforate  the  sterno-mastoid  muscle  at  its 
upper  part,  and,  uniting  with  the  anterior  cervical  plexus, 
is  distributed  to  the  trapezius  muscle  (p.  41). 

The  INTERNAL  CAROTID  ARTERY  ascends  vertically  from 
the  upper  border  of  the  thyroid  cartilage  to  the  base  of 
the  skull ;  the  rectus  capitis  anticus  major  muscle  separates 
it  from  the  vertebrae ;  except  at  its  commencement,  where 


DEEP    CERVICAL    REGION.  53 

it  has  a  fusiform  dilatation,  it  maintains  the  same  size 
throughout,  and  gives  off  no  branches  ;  it  enters  the  carotid 
canal  of  the  temporal  bone  to  emerge  in  the  cranial  cavity 
for  the  supply  of  the  orbit  and  the  encephalon.  This 
vessel  is  sometimes  tortuous  instead  of  straight. 

The  ascending  pharyngeal  artery,  seen  in  this  dissection, 
is  a  branch  of  the  external  carotid,  given  off  just  as  the 
common  carotid  bifurcates.  It  ascends,  between  the  inter- 
nal carotid  and  the  pharynx,  upon  the  spinal  column ;  it 
gives  a  branch  to  the  pharynx,  and  near  the  skull,  where 
it  becomes  tortuous,  it  sends  a  branch  through  the  foramen 
lacerum  posterius  to  supply  the  posterior  fossa  of  the 
skull  (p.  45). 

The  HYPOGLOSSAL  NERVE  lies  deep  beneath  the  internal 
carotid  ;  it  issues  from  the  skull  at  the  anterior  condyloid 
foramen,  passes  between  the  vein  and  artery,  and  descend- 
ing curves  round  the  occipital  artery,  and  becomes  super- 
ficial at  the  lower  border  of  the  posterior  belly  of  the 
digastricus  muscle,  from  whence,  passing  between  the 
mylo-hyoid  and  hyo-glossus  muscles,  it  is  directed  forward 
to  the  tongue  and  its  muscles. 

The  SYMPATHETIC  NERVE  in  the  neck  consists  of  a  gan- 
gliated  cord,  which  lies  close  to  the  spinal  column  ;  it  is 
continuous  with  a  similar  gangliated  cord  in  the  thorax, 
and  with  several  ganglionic  bodies  in  the  head  connected 
with  the  three  trunks  of  the  fifth  nerve.  The  cervical 
portion  of  the  sympathetic  has  three  ganglia ;  the  superior 
one  is  fusiform  in  shape,  and  an  inch  or  more  in  length ;  it 
is  placed  on  the  reetus  capitis  anticus  major  muscle,  beneath 
the  internal  carotid  artery  and  the  trunks  of  the  eighth 
nerve,  which  must  be  raised  to  expose  it.  It  is  connected 
with  the  other  nerves,  spinal  as  well  as  cranial,  by  minute 
filaments ;  some  of  these,  called  nervi  molles,  ramify  upon 
the  branches  of  the  carotid  artery,  and  form  plexuses  on 
their  subdivisions.  It  sends  a  branch  downward,  behind 
the  sheath  of  the  carotid,  to  the  heart,  called  the  superior 
cardiac  nerve. 

The  middle  cervical  ganglion  is  situated  opposite  the  fifth 
cervical  vertebra,  lying  upon  or  near  the  inferior  thyroid 
artery,  whence  it  is  sometimes  called  the  thyroid  ganglion  ; 
it  is  of  a  rounded  shape,  and  gives  off  branches  which  con- 
nect with  the  spinal  nerves,  and  ramify  upon  the  thyroid 
artery ;  it  also  gives  off  the  middle  cardiac  nerve,  which 
descends  to  the  thorax,  crossing  the  subclavian  artery, 

5* 


54  ANATOMY    OF    THE    HEAD     AND     NECK. 

and  terminates  in  the  cardiac  plexus.     The  middle  gan- 
glion is  sometimes  wanting. 

The  inferior  cervical  ganglion  occupies  the  interval 
between  the  first  rib  and  the  transverse  process  of  the 
seventh  cervical  vertebra,  and  will  be  seen  in  a  later  stage 
of  the  dissection,  (p.  59.) 


DISSECTION  VIII. 

The  upper  portion  of  the  sternum  should  now  be  removed,  with  the 
sternal  half  of  the  clavicle  attached,  and  the  ribs  cut  away  on  each 
side  as  far  as  the  insertions  of  the  scaleni  muscles  ;  this  will  expose 
the  deep  vessels  of  the  neck  in  their  relation  to  the  heart ;  the  cellu- 
lar tissue  which  covers  them  is  to  be  carefully  removed  by  following 
the  vessels  downward  from  the  point  at  which  they  are  already  dis- 
sected in  the  neck.  The  sterno-clavicular  articulation  should,  how- 
ever, be  first  examined,  and  this  may  be  done  before  it  is  detached 
from  the  thorax. 

STERNO-CLAVICULAR   ARTICULATION. 

The  internal  extremity  of  the  clavicle  is  strongly  con- 
nected with  the  upper  bone  of  the  sternum  by  several 
ligaments. 

The  anterior  sterno-clavicular  ligament  is  a  stout  band 
of  fibres,  passing  from  the  anterior  surface  of  the  sternal 
end  of  the  clavicle,  downward  and  inward,  to  the  upper 
and  anterior  part  of  the  first  bone  of  the  sternum. 

The  posterior  sterno-clavicular  ligament,  less  developed 
than  the  preceding,  occupies  a  situation,  and  has  a  similar 
origin  and  insertion  on  the  inner  aspect  of  the  articulation. 

The  inter-clavicular  ligament  is  a  strong  rounded  cord, 
intervening  between  the  superior  surfaces  of  the  clavi- 
cles, and  is  closely  attached  to  the  incisura  semilunaris  of 
the  sternum. 

The  costo-clavicular  ligament  is  a  band  passing  obliquely 
forward  from  the  under  surface  of  the  clavicle  at  its  sternal 
end,  to  the  cartilage  of  the  first  rib ;  sometimes  the  clavicle 
touches  the  rib,  and  has  an  articular  surface  at  this  point ; 
the  subclavius  muscle  lies  in  front  of  this  ligament. 

An  inter-articular  fibro-cartilage  will  be  found  on  divid- 
ing these  ligaments  and  detaching  the  clavicle;  it  is  nearly 
circular  in  form,  and  thicker  in  the  centre  than  at  its  cir- 
cumference ;  it  is  adherent  by  its  edges  to  the  ligaments 
which  surround  the  articulation.  Its  sternal  surface  is 


BASE     OF     THE     NECK.  55 

much  more  convex  than  its  clavicular,  which  is  nearly  flat, 
and  corresponds  to  a  concavity  in  the  sternum,  so  that  the 
articulation  in  reality  is  between  the  sternum  and  the  flbro- 
cartilage,  and  not  between  the  sternum  and  clavicle. 

The  inter-articular  cartilage  divides  the  joint  into  two 
separate  parts,  each  provided  with  a  separate  synovial 
membrane. 

BASE    OF    THE    NECK. 

At  the  root  of  the  neck,  the  region  exposed  behind  the 
articulation  above  described,  will  exhibit  the  great  venous 
branches  which  return  the  blood  from  the  head  and  upper 
extremity. 

The  internal  jugular  vein  descends  the  neck  on  the  outer 
side  of  the  carotid  artery,  and  enters  the  subclavian  vein, 
which  is  the  continuation  of  the  axillary  vein ;  the  internal 
jugular  vein  at  this  point  is  provided  with  two  valves. 

The  SUBCLAVIAN  VEIN  lies  in  front  of  the  artery  of  that 
name,  and  the  union  of  Jthis  with  the  preceding  vein  forms 
the  VENA  INNOMINATA.  The  vena  innominata  is  further 
reinforced  by  the  vertebral  vein,  which  descends  at  the  side 
of  the  vertebral  artery  through  the  foramina  of  the  trans- 
verse processes  of  the  cervical  vertebrae,  and  by  the  infe- 
rior thyroid  veins,  coming  from  the  thyroid  body  and  its 
neighborhood.  The  two  venae  innominatae  unite  to  form 
the  SUPERIOR  YENA  CAVA,  and,  owing  to  the  destination 
of  that  vessel  to  the  right  auricle,  the  vena  innominata  of 
the  left  side  is  longer  than  that  of  the  right,  and  its 
direction  more  nearly  transverse ;  it  lies  upon  the  three 
primary  branches  of  the  aorta,  and  upon  the  upper  part  of 
the  arch  itself.  The  thoracic  duct  enters  the  left  vena  in- 
nominata at  its  commencement ;  the  precise  point  may  be 
demonstrated  by  inflating  the  duct  in  the  thorax  with  a 
blow-pipe.  The  ductus  lymphaticus  dexter,  which  is  the 
termination  of  the  lymphatic  vessels  of  the  right  side  of 
the  head  and  neck,  right  arm,  and  right  side  of  the  thorax, 
enters  the  right  vena  innominata  near  its  commencement. 
The  orifices  of  both  these  lymphatic  ducts  are  provided 
with  sigmoid  valves  to  prevent  admission  of  blood. 

Between  the  subclavian  vein  and  artery  may  be  traced 
the  pneumogastric  and  phrenic  nerves. 

The  pneumogastric  nerve  has  been  already  seen  higher  in 
the  neck,  lying  between  the  carotid  artery  and  internal 
jugular  vein  (p.  52);  its  lower  part  is  now  to  be  observed. 


56      ANATOMY  OF  THE  HEAD  AND  NECK 

It  follows  a  course  a  little  different  on  one  side  from  that 
on  the  other ;  on  the  right  side  the  nerve  passes  in  front  of 
the  subclavian  artery,  between  it  and  the  vein ;  on  the  left 
side  it  passes  between  the  left  subclavian  and  common 
carotid,  and  then  crosses  the  arch  of  the  aorta ;  below  these 
points  the  two  nerves  resemble  each  other  in  their  course, 
which  is  behind  the  root  of  the  lung,  along  the  oesophagus, 
to  the  stomach.  As  the  right  pneumogastric  crosses  the 
subclavian,  it  gives  off  the  recurrent  laryngeal  branch  which 
curves  around  that  vessel,  and  is  reflected  upward  to  the 
larynx ;  on  the  left  side  this  branch  is  given  off  as  the  nerve 
crosses  the  aorta,  and  it  curves  around  its  arch  at  the  point 
where  the  ductus  arteriosus  is  obliterated,  to  ascend  like 
its  fellow.  In  their  course  upward  the  recurrent  branches 
lie  on  the  inner  side  of  the  carotids,  between  the  oesopha- 
gus and  the  trachea,  to  both  of  which  they  give  branches  ; 
they  terminate  by  filaments  distributed  to  all  the  muscles 
of  the  larynx  except  the  crico-thyroid,  which  is  supplied  by 
the  superior  laryngeal  nerve. 

The  PHRENIC  NERVE  is  a  medium-sized  nerve  arising  from 
the  anterior  trunks  of  the  third  and  fourth  cervical  nerves, 
and  occasionally  from  the  fifth  ;  it  descends  obliquely  upon 
the  anterior  scalenus  muscle,  crossing  from  its  outer  to  its 
inner  edge,  and  enters  the  thorax  between  the  subclavian 
artery  and  vein,  passing  in  front  of  the  root  of  the  lung, 
upon  the  pericardium,  to  the  diaphragm,  to  which  it  is  dis- 
tributed. 

The  ARCH  OF  THE  AORTA  gives  rise  to  three  vessels, 
collectively  known  as  the  brachio-cephalic  trunks ;  the  in- 
nominata,  the  left  carotid,  and  the  left  subclavian  ;  the 
number  is  sometimes  increased  by  the  left  vertebral,  which 
in  a  certain  number  of  instances  arises  from  the  aorta,  in- 
stead of  from  the  left  subclavian ;  when  this  irregularity 
takes  place  the  supernumerary  vessel  is  usually  given  off 
between  the  carotid  and  subclavian  arteries.  Occasionally, 
the  number  of  primary  branches  is  reduced  to  two.  A  very 
slight  interval  separates  the  aortic  trunks  from  each  other. 

The  INNOMINATA  ARTERY  is  a  short  trunk,  three  quarters 
of  an  inch  in  length;  it  lies  upon  the  trachea,  which  it 
crosses  somewhat  obliquety,  and  then  divides  into  the  right 
carotid  and  right  subclavian  arteries.  The  innominata 
occasionally  gives  off  a  branch  called  the  middle  thyroid, 
which  ascends  tortuously  in  front  of  the  trachea  to  the 
thyroid  body ;  the  existence  of  this  anomalous  branch,  it 


BASE    OP    THE    NECK.  57 

will  at  once  be  seen,  might  essentially  complicate  the  ope- 
ration of  tracheotomy. 

The  COMMON  CAROTID  ARTERIES  will  be  seen  to  have  a 
different  origin,  the  right  being  from  the  innominata  and 
the  left  directly  from  the  aorta  ;  the  right  is  consequently 
shorter  than  the  left  by  the  length  of  the  innominata. 
Separated  at  first  only  by  the  width  of  the  trachea,  they 
diverge  as  they  ascend,  their  relations,  except  at  their  ori- 
gin, being  the  same  on  the  two  sides  (p.  42).  The  right 
carotid  occasionally  arises  directly  from  the  aorta. 

The  SUBCLAVIAN  ARTERY  differs,  not  only  in  origin,  but 
in  direction,  on  the  two  sides  of  the  body,  the  right  coming 
from  the  innominata  and  the  left  from  .the  aorta  direct ;  the 
right,  moreover,  is  shorter  than  the  left  by  the  length  of  the 
innominata.  The  left  subclavian  ascends  horizontally,  and 
then  turning  suddenly,  forms  a  right  or  an  obtuse  angle, 
while  the  right  describes  a  gradual  and  regular  curve. 
On  both  sides  the  artery  passes  beneath  the  scalenus  anti- 
cus  muscle,  and  rests  upon  the  first  rib,  which  is  slightly 
grooved  at  the  point  where  it  reposes.  The  scalenus  mus- 
cle separates  the  artery  from  its  vein,  which  lies  in  front 
of  the  muscle ;  behind  the  artery  are  the  scalenus  posticus 
muscle,  and  the  branches  of  the  brachial  plexus  of  nerves, 
which  in  a  measure  surround  it.  At  the  lower  border  of 
the  first  rib  the  subclavian  becomes  the  axillary  artery. 
The  right  subclavian  has  been  observed  to  spring  from  the 
aorta  direct,  and  is  then  most  frequently  the  last  in  order 
of  the  primary  aortic  trunks ;  in  such  a  case  it  crosses  the 
neck  obliquely,  in  front  of  the  vertebral  column  and  be- 
neath the  oesophagus,  to  regain  its  usual  position.  When 
this  anomaly  exists  the  carotid  arteries  not  unfrequently 
spring  from  a  common  trunk,  very  short,  and  showing  some 
marks  of  a  tendency  to  divide.  The  left  subclavian  may 
arise  in  common  with  the  left  carotid. 

The  student  should  explore  with  his  finger  the  tubercle 
on  the  first  rib  into  which  the  scalenus  anticus  muscle  is 
inserted,  this  being  the  guide  to  the  position  of  the  sub- 
clavian artery,  when  the  surgeon  desires  to  place  a  ligature 
upon  it.  He  should  also  note  the  relations  of  the  artery 
to  the  subclavian  vein,  the  brachial  plexus  of  nerves,  the 
scalenus  muscle,  the  clavicle,  and  the  rib. 

At  this  period  of  the  dissection  may  be  observed  the 
variable  height  to  which  the  pleural  cavity  sometimes  ex- 
tends above  the  first  rib ;  a  prolongation  of  two  or  even 


58  ANATOMY    OP    THE    HEAD    AND     NECK. 

three  inches  has  been  observed.  It  will  be  seen  that  when 
such  is  the  case,  the  thoracic  cavity  might  easily  be  opened 
in  the  course  of  any  operation  in  this  locality. 

The  subclavian  artery  gives  origin  to  the  following 
branches,  viz: — 

Vertebral,  Internal  Mammary, 

Thyroid  Axis,  Superior  Intercostal. 

The  vertebral  artery,  the  first  and  largest  of  the  branches,  ascends 
the  neck  upon  the  transverse  processes  of  the  cervical  vertebrae  until 
it  reaches  the  sixth,  when  it  enters  the  vertebral  foramen  and  follows 
the  caual  formed  by  these  foramina  as  far  as  the  atlas  ;  having  passed 
through  the  foramen  of  the  atlas,  it  curves  around  its  articulating  pro- 
cess, perforates  the  posterior  occipito-atloid  ligament,  as  well  as  the  dura 
mater,  and  enters  the  foramen  magnum  to  unite  with  the  vertebral  of 
the  other  side  in  forming  the  basilar  artery.  In  the  canal  it  lies  in . 
front  of  the  anterior  trunks  of  the  cervical  nerves,  except  the  first  and 
second,  the  former  of  which  it  crosses  on  its  inner,  the  latter  on  its 
outer  side.  In  its  course  the  vertebral  artery  gives  off  branches  to  the 
membranes  of  the  spinal  cord  and  the  deep  muscles  of  the  cervical 
region,  and  a  posterior  meningeal  branch  to  the  posterior  fossa  of  the 
cranial  cavity  and  falx  cerebelli.  Occasionally  this  artery  does  not 
enter  the  vertebral  foramen  till  it  has  reached  a  point  higher  than  the 
sixth  vertebra.  The  arteries  of  the  two  sides  may  vary  in  size,  in 
which  case  it  is  ordinarily  the  left  which  is  largest ;  one  of  them 
may  also,  as  has  been  stated,  arise  from  the  aorta ;  this  irregularity 
has  rarely  been  noticed  except  upon  the  left  side. 

The  thyroid  axis  springs  from  the  subclavian,  close  to  the  inner  side 
of  the  scalenus  anticus  muscle ;  it  does  not  always  exist,  as  the 
branches  to  which  it  gives  rise  are  not  unfrequently  given  off  directly 
from  the  subclavian;  they  are  the — 

Inferior  thyroid, 
Supra-scapular, 
Transversalis  cervicis. 

The  inferior  thyroid  artery,  a  vessel  of  considerable  size,  passes  ob- 
liquely inward,  behind  the  common  carotid,  to  the  thyroid  body,  which 
it  penetrates  at  its  posterior  surface,  and  in  the  substance  of  which  it 
anastomoses  with  its  fellow  of  the  opposite  side,  and  with  the  supe- 
rior thyroid,  a  descending  branch  from  the  external  carotid  ;  in  its 
course  it  supplies  a  branch  called  the  anterior  cervical  to  the  posterior 
aspect  of  the  trachea.  The  place  of  this  artery  is  sometimes  taken  by 
a  trunk  called  the  middle  or  lowest  thyroid,  or  thyroid  of  Neubauer,  and 
which,  springing  from  the  innominata  or  the  aorta,  ascends  in  front  of 
the  trachea  to  the  lower  part  of  the  thyroid  body.  This  branch  may 
be  present  also  without  the  absence  of  the  inferior  thyroid. 

The  supra-scapular  artery  is  a  large  branch  which  passes  outward, 
behind  the  clavicle,  to  the  scapula,  where,  crossing  the  supra-scapular 
notch,  it  is  distributed  to  the  dorsum  of  the  scapula,  as  is  described 
in  Part  Second,  Dissection  VI. 

The  transrersaliit  cervicis  artery,  also  a  large  branch,  crosses  the  neck 
higher  than  the  preceding,  and  divides  into  two  branches,  the  superjl- 


BASE     OP    THE     NECK.  59 

cialis  cervicis,  distributed  to  the  under  surface  of  the  trapezius  mus- 
cle, and  the  posterior  scapular,  which  passes  beneath  the  levator  anguli 
scapulae  muscle  and  turns  downward  along  the  base  of  the  scapula, 
as  is  described  in  Part  Second,  Dissection  V.  The  posterior  scapular 
sometimes  arises  as  a  separate  trunk  from  the  subclavian,  outside  of 
the  scalenus  anticus  muscle ;  in  this  case  the  transversalis  cervicis 
is  of  small  size. 

The  superior  intercostal  artery  is  a  descending  branch  of  the  subcla- 
vian, and  can  only  be  seen  satisfactorily  by  cutting  away  the  ribs  in 
front ;  it  turns  over  the  neck  of  the  first  rib  and  supplies  two,  and 
occasionally  three  of  the  upper  intercostal  spaces. 

The  prof  undo,  cervicis  artery  usually  arises  in  common  with  the  pre- 
ceding branch,  although  it  may  arise  independently  from  the  subcla- 
viau  ;  it  passes  between  the  transverse  processes  of  the  seventh 
cervical  and  first  dorsal  vertebra?,  and  ascends  the  neck  between  the 
complexus  and  semi-spinalis  colli  muscles,  to  anastomose  with  a  de- 
scending branch  of  the  occipital  artery,  called  the  princeps  cervicis. 
(See  Part  Second,  Dissection  V.) 

The  internal  mammary  artery  is  a  large  descending  branch  given  off 
from  the  subclavian,  and  although  sometimes  arising  from  the  thy- 
roid axis,  or  in  common  with  the  subscapular,  is  very  constant  in  its 
mode  of  origin  ;  it  is  distributed  to  the  inner  surface  of  the  anterior 
portion  of  the  thorax,  and  is  described  in  Part  Second,  Dissection  III. 

The  inferior  cervical  ganglion,  the  third  of  the  cervical 
ganglia  of  the  sympathetic  nerve  (p.  54),  lies  behind  the 
superior  intercostal  artery  in  the  interval  between  the  first 
rib  and  the  transverse  process  of  the  seventh  cervical  ver- 
tebra. It  is  the  largest  of  the  three  and  irregularly  rounded 
in  shape ;  it  is  united  with  the  middle  cervical  ganglion  and 
with  the  chain  of  ganglia  in  the  thorax.  It  gives  off  the 
inferior  cardiac  nerve,  which,  after  joining  the  recurrent 
laryngeal  branch  of  the  pneumogastric  nerve,  is  continued 
to  the  deep  cardiac  plexus  lying  upon  the  trachea,  below 
the  arch  of  the  aorta. 

The  BRACHIAL  PLEXUS  can  be  better  examined  as  to  its 
origin  and  plan  of  formation  at  this  period  of  the  dissec- 
tion than  in  connection  with  the  axilla.  It  is  formed  by 
the  union  of  the  anterior  branches  of  the  last  four  cervical 
and  first  dorsal  nerves ;  the  fifth  and  sixth  nerves  emerging 
from  the  inter- vertebral  foramina  descend  obliquely  to  unite 
in  a  trunk  which  speedily  bifurcates ;  the  eighth  cervical 
and  first  dorsal  ascend  obliquely  to  unite  in  a  large  trunk 
which  also  bifurcates ;  the  seventh  continues  by  itself  as 
far  as  the  first  rib,  and  then  bifurcates,  one  branch  uniting 
with  the  lower  bifurcation  resulting  from  the  union  of  the 
fifth  and  sixth  nerves,  and  its  other  branch  uniting  with 
the  upper  bifurcation  resulting  from  the  union  of  the  eighth 


60  ANATOMY    OF    THE    HEAD    AND    NECK. 

cervical  and  first  dorsal  nerves.   We  thus  have  four  branch( 
representing  five  original  trunks. 


DISSECTION  IX. 

The  section  known  in  the  French  amphitheatres  as  the  coupe  (hi 
pharynx  is  now  to  be  made.  The  trachea  and  oesophagus,  being  divi led 
opposite  the  top  of  the  sternum,  are  to  be  turned  up  over  the  face ; 
the  chisel  is  to  be  applied  at  the  apex  of  the  angle  formed  by  the 
upper  part  of  these  and  the  vertebral  column,  and,  keeping  it  close  to 
the  latter,  the  basilar  process  is  to  be  broken  through  behind  the  sella 
turcica:  the  skull  is  then  to  be  separated  into  two  halves,  one  ante- 
rior and  the  other  posterior,  by  a  section  with  the  saw  carried  behind 
the  styloid  process  and  directed  inward  and  a  little  forward  ;  the  two 
sides  should  be  sawed  separately  and  the  two  incisions  should  meet 
where  the  basilar  process  has  been  cut  through  with  the  chisel;  the 
occiput  and  vertebral  column  will  then  constitute  one  of  the  pieces, 
while  the  other  will  be  made  up  of  the  face,  tongue,  trachea,  and 
pharynx. 

Upon  the  latter  of  these  pieces,  the  student  should  exa- 
mine the  lips,  to  see  the  frena  formed  by  the  mucous 
membrane  and  which  attaches  them  to  the  lower  and 
upper  jaws  upon  the  median  line.  The  orifice  of  Steno's 
duct,  in  the  cheek  (p.  24),  near  the  second  molar  tooth  of 
the  upper  jaw,  should  also  be  sought  for  and  explored  by 
probing. 

PHARYNX. 

The  lower  jaw  should  be  removed,  except  about  half  an  inch  ou 
each  side  of  the  symphysis.  The  pharynx  should  be  stuffed  with  tow, 
cotton-wool,  or  like  material ;  and,  when  thus  distended,  the  con- 
strictor muscles  will  be  easily  dissected. 

The  PHARYNX  is  the  dilated  upper  extremity  of  the  ali- 
mentary* tube,  extending  from  the  cavity  of  the  mouth  to 
the  oesophagus,  about  four  and  a  half  inches ;  its  inner 
surface  is  lined  with  mucous  membrane,  continuous  with 
that  of  the  mouth  and  oesophagus,  and  its  walls  are  formed 
by  muscles  called  constrictors. 

The  constrictor  muscles  are  three  in  number  on  each 
side,  and  are  so  arranged  that  the  lower  overlaps  the  mid- 
dle, and  the  middle  the  upper  muscle ;  they  are  attached 
superiorly  by  an  aponeurotic  expansion  to  the  base  of  the 
skull,  and  anteriorly  to  the  larynx,  hyoid  bone,  tongue,  and 
bones  of  the  nasal  cavity. 


in 

a 


PHARYNX.  61 

The  CONSTRICTOR  INFERIOR  is  the  most  superficial  of  the 
three  muscles;  it  arises  from  the  side  of  the  cricoid  carti- 
lage, and  from  the  oblique  line  and  upper  and  lower  borders 
of  the  ala  of  the  thyroid  cartilage ;  from  this  origin  the 
bres  are  directed  backward  in  a  radiated  manner  to  meet 

ose  of  the  corresponding  muscle  of  the  opposite  side. 
hey  unite  and  form  a  tendinous  raphe  along  the  posterior 
median  line  of  the  pharynx.  The  lower  fibres  are  continu- 
ous with  the  muscular  fibres  of  the  oesophagus.  The  recur- 
rent laryngeal  nerve  passes  under  its  lower  border. 

The  CONSTRICTOR  MEDIUS  arises  from  the  greater  cornu 
of  the  os  hj'oides,  and  from  the  stylo-hyoid  ligament ;  its 
fibres  radiate  from  this  origin,  and  blend  along  the  middle 
line  with  the  muscle  of  the  other  side,  ending  at  its  upper 
border  in  the  aponeurosis  of  the  pharynx.  Tiie  glosso- 
pharyngeal  nerve  passes  under  the  upper  border  of  this 
muscle,  and  the  stylo-phaiyngeus  muscle  separates  it  from 
the  superior  constrictor. 

The  stylo-pharyngeus  muscle,  already  described  (p.  51), 
is  again  seen  in  this  connection ;  arising  from  the  base  of  the 
styloid  process,  and  descending  between  the  superior  and 
middle  constrictor,  it  is  inserted  partly  into  the  pharynx, 
and  partly  into  the  upper  border  of  the  thyroid  cartilage, 

The  stylo-hyoid  ligament,  already  described  (p.  51),  is 
again  seen  extending  from  the  tip  of  the  styloid  process  of 
the  temporal  bone  to  the  lesser  cornu  of  the  os  hyoldes. 

The  CONSTRICTOR  SUPERIOR  arises  from  the  inner  surface 
of  the  internal  pterygoid  plate,  from  the  pterygo-maxillary 
ligament,  the  mucous  membrane  of  the  side  of  the  mouth, 
mid  from  the  posterior  part  of  the  mylo-hyoid  ridge  of  the 
lower  jaw ;  from  this  extensive  and  irregular  origin  its 
fibres  pass  backward,  and  are  inserted  into  the  pharyngeal 
aponeurosis.  The  portion  arising  from  the  mucous  mem- 
brane of  the  mouth  has  been  described  as  a  separate  mus- 
cle, called  the  glosso-pharyngeus. 

The  pterygo-maxillary  ligament  is  the  raphe  of  union 
which  exists  between  the  superior  constrictor  and  the  bucci- 
nator muscles,  one  extremity  being  attached  to  the  hamular 
process  of  the  internal  pterygoid  plate,  and  the  other  to 
the  extremity  of  the  molar  ridge  of  the  lower  jaw. 

The  pharyngeal  aponeurosis  connects  the  muscular  part 
of  the  pharynx  with  the  base  of  the  skull,  being  attached 
superiorly  to  the  basilar  process  of  the  occipital  bone  and 
6 


62      ANATOMY  OF  THE  HEAD  AND  NECK 


the  petrous  portion  of  the  temporal  bone,  and  inferiorly 
losing  itself  in  the  muscular  strata  of  the  pharynx. 

The  pharynx  is  now  to  be  laid  tfpen  along  the  posterior  median 
line  ;  it  is  also  to  be  dissected  away,  for  a  short  distance  on  each  side, 
from  its  aponeurotic  attachment  to  the  occipital  bone. 

The  pharynx  terminates  in  the  oesophagus  by  a  constric- 
tion opposite  the  cricoid  cartilage.  The  mucous  membrane 
of  the  pharynx  is  thicker,  redder,  and  more  abundantly  sup- 
plied with  muciparous  glands  than  that  of  the  oesophagus. 

The  (ESOPHAGUS  lies  upon  the  bodies  of  the  vertebne 
behind  the  trachea,  and,  with  two  or  three  slight  lateral 
curvatures,  extends  downward  about  nine  inches  to  termi- 
nate in  the  stomach.  Its  walls,  like  those  of  the  alimentary 
canal  elsewhere,  are  composed  of  three  layers,  viz.,  muscular, 
cellular,  and  mucous.  The  muscular  coat  consists  of  longi- 
tudinal and  circular  fibres;  these  are  red  and  well  marked 
near  the  pharynx,  but  pale  and  indistinct  as  they  approach 
the  stomach.  At  the  upper  part,  the  longitudinal  fibres, 
which  are  external,  are  arranged  in  three  fasciculi,  one  ante- 
rior, arising  from  the  cricoid  cartilage,  and  two  lateral,  con- 
tinuous with  the  inferior  constrictor  muscle  of  the  pharynx. 
The  circular,  or  internal  fibres,  are  also  continuous  with 
those  of  the  inferior  constrictor.  The  mucous  coat  is  very 
movable,  and  when  not  distended  is  thrown  into  longitu- 
dinal folds,  so  that  the  sides  of  the  tube  come  in  contact 
with  each  other. 

The  section  of  the  pharynx  exposes  the  posterior  aper- 
tures of  the  nasal  cavity,  divided  by  the  septum  nasi.  On 
each  side  of  this  will  be  found  the  trumpet-shaped  orifice 
of  the  Eustachian  tube ;  if  the  mucous  membrane  is  re- 
moved, it  will  be  found  that  this  tube  is  composed  of  carti- 
lage, and  is  nearly  an  inch  in  length ;  it  is  attached  supe- 
riorly to  a  groove  between  the  sphenoid  and  the  petrous 
portion  of  the  temporal  bone,  through  which  it  communi- 
cates with  the  cavity  of  the  tympanum.  A  bundle  of 
muscular  fibres,  extending  from  the  lower  border  of  the 
Eustachian  tube  to  the  palato-pharyngeus  muscle,  is  called 
the  salpingo-pharyngeus  muscle ;  it  does  not  always  exist. 

PALATINE   REGION. 

The  ISTHMUS  FAUCIUM  is  the  constriction  between  the 
mouth  and  the  upper  part  of  the  pharynx,  formed  above 
\)y  the  soft  palate,  and  below  by  the  tongue. 


PALATINE    REGION.  63 

The  SOFT  PALATE,  or  VELUM  PENDULUM  PALATI,  is  a 
dependent  structure  which  intervenes  between  the  mouth 
and  the  pharynx;  it  is  continuous  with  the  roof  of  the 
mouth,  or  hard  palate,  superiorly ;  interiorly  its  border 
is  free,  and  from  its  centre  hangs  a  pendulous  body  called 
the  uvula.  Two  folds  spring  from  each  side  of  the  uvula, 
and  are  continued  downward  on  the  sides  of  the  isthmus 
faucium  ;  these  are  the  arches  or  pillars  of  the  palate,  the 
anterior  reaching  the  side  of  the  tongue  at  its  root,  and  the 
posterior  being  continuous  with  the  side  of  the  pharynx. 
Between  these  pillars  lies  the  tonsil. 

The'  TONSIL  is  a  collection  of  mucous  follicles,  forming  a 
body,  rounded  in  shape,  but  variable  in  size ;  the  apertures 
of  the  follicles  are  sometimes  very  apparent ;  it  is  placed 
just  above  the  tongue,  and  corresponds  with  the  angle  of 
the  jaw  externally. 

The  muscles  of  the  palate  are  difficult  of  dissection,  on  account  of 
their  small  size,  and  their  close  connection  with  surrounding  parts. 
The  upper  attachment  of  the  pharynx,  with  the  superior  constnctor, 
must  be  removed  ;  the  mucous  membrane  of  the  posterior  surface  of 
the  soft  palate  is  to  be  raised  with  great  care,  so  as  not  to  injure  the 
muscular  or  tendinous  fibres  which  compose  the  greater  part  of  its 
substance ;  it  may  be  made  tense  for  dissection  by  drawing  down  and 
fastening  the  uvula  with  a  hook  or  pin. 

The  LEVATOR  PALATI  arises  from  the  under  surface  of 
the  apex  of  the  petrous  portion  of  the  temporal  bone,  and 
from  the  cartilage  of  the  Eustachian  tube ;  it  then  passes 
down  by  the  side  of  the  posterior  nares,  and  spreads  out 
in  the  structure  of  the  soft  palate  as  far  as  the  median 
line. 

The  TENSOR  PALATI  arises  from  the  scaphoid  fossa  at 
the  base  of  the  pterygoid  plate,  and  from  the  outer  part  of 
the  Eustachian  tube ;  it  terminates  in  a  tendon  which  winds 
round  the  hamular  process  of  the  pterygoid  plate,  and,  ex- 
panding into  an  aponeurosis,  is  inserted  into  the  posterior 
border  of  the  horizontal  portion  of  the  palate  bone ;  it 
also,  with  the  muscle  of  the  opposite  side,  helps  to  form 
the  aponeurotic  basis  of  the  soft  palate,  lying  beneath  the 
tendon  of  the  preceding  muscle. 

The  PALATO-PHARYNGEUS  MUSCLE  forms  the  posterior 
pillar  of  the  soft  palate ;  it  arises  by  a  broad  expansion 
from  the  lower  part  of  the  soft  palate,  and,  joining  with 
the  stylo-pharyngeus  muscle,  is  inserted  into  the  posterior 
border  of  the  thyroid  cartilage. 

The  AZYGOS  UVULAE,  situated  upon  the  posterior  surface 


G4  ANATOMY     OP     THE     HEAD     AND     NECK. 

along  the  middle  line  of  the  soft  palate,  consists  of  two 
bundles  of  very  pale  fibres,  arising  from  the  spine  at  the 
posterior  border  of  the  hard  palate,  and  terminating  at  the 
free  extremity  of  the  uvula. 

The  PALATO-GLOSSUS  MUSCLE,  or  CONSTRICTOR  ISTHMI 
FAUCIUM,  forms  the  projection  of  the  anterior  pillar  of  the 
soft  palate  ;  it  arises  from  the  aponeurosis  of  the  soft  palate 
in  front  of  the  tensor  pal'ati,  and  is  inserted  into  the  lateral 
surface  and  dors um  of  the  tongue. 

OTIC  AND  MECKEL'S  GANGLIA. 

The  tongue,  hyoid  bone,  and  larynx,  may  now  be  separated  from 
the  portion  of  the  skull  to  which  they  are  attached,  and  reserved 
for  further  examination.  The  spheno-maxillary  fossa  is  to  be  searched 
for  certain  ganglia  of  the  sympathetic  system. 

The  OTIC,  or  ARNOLD'S  GANGLION,  if  not  already  exa- 
mined in  connection  with  the  inferior  maxillary  nerve,  will 
be  found  as  a  small  ovoid  body  just  below  the  foramen 
ovale,  on  the  inner  side  of  the  inferior  maxillary  nerve, 
and  at  the  point  where  it  is  joined  by  the  second  root  of 
the  trifacial  nerve.  This  ganglion  gives  branches  to  the 
tensor  tympani  and  tensor  palati  muscles,  communicates 
with  the  nerves  of  its  vicinity,  and  sends  a  branch  to  the 
Vidian  nerve,  called  nervus  petrosus  xuperficialis  minor  ; 
but  its  connections  are  by  twigs  so  minute  that  their  exa- 
mination can  only  be  accomplished  by  the  aid  of  a  lens 
and  by  a  special  dissection. 

In  the  spheno-maxillary  fossa,  and  connected  by  short 
branches  with  the  superior  maxillary  nerve,  is  the  spheno- 
palaMne,  or  MeckeVs  ganglion ;  it  lies  below  the  superior 
maxillaiy  nerve,  above  the  posterior  palatine  canal,  and 
outside  the  spheno-palatine  foramen ;  its  branches  are 
directed  upward  to  the  orbit,  downward  to  the  mouth, 
inward  to  the  nose,  and  backward  to  the  pharynx  and 
Yidian  canal;  the  principal  of  these  are  as  follows: — 

The  large  palatine  branch  passes  through  the  posterior  palatine 
canal  and  forward  along  the  roof  of  the  mouth  nearly  to  the  incisor 
teeth,  where  it  unites  with  the  naso-palatine  branch  of  the  same  gan- 
glion. The  small  palatine  branch  descends  to  supply  the  soft  palate, 
the  tonsils,  and  the  uvula. 

The  naso-palatine  branch  crosses  the  roof  of  the  nasal  fossa  to  the 
septum  nasi,  on  the  side  of  which  it  descends  to  the  anterior  palatine 
canal,  where  it  unites  with  the  large  palatine  branch. 

The  Vidian  nerve  passes  through  the  Vidian  or  pterygoid  canal, 
then  enters  the  cranium  through  the  cartilaginous  tissue  "closing  the 


i/w 

'1 


N  A  S  A  L    F  0  S  S  JE  .  65 

foramen  lacerum  anterius,  and,  lying  in  a  groove  on  the  surface  of  the 
petrous  portion  of  the  temporal  bone,  takes  the  name  of  nervus  petrosus 
su/H-rficialis  major,  and  enters  the  hiatus  Fallopii  to  join  the  gangli- 
fonn  enlargement  of  the  facial  nerve. 

These  branches  can  hardly  be  found  except  by  a  special  dissection. 

Before  discarding  the  piece  of  bone  which  the  student 
has  just  been  examining,  he  should  open  the  carotid  canal 
to  see  the  temporal  portion  of  the  internal  carotid  artery. 
'he  canal  can  be  opened  by  bone  forceps,  or  by  a  small 

isel  carefully  handled.  The  artery  at  first  ascends,  is 
then  directed  forward  horizontally,  and  lastly  turns  upward 
into  the  cranium.  In  the  canal  it  is  surrounded  by  branches 
from  the  superior  cervical  ganglion  of  the  sympathetic 
nerve ;  it  gives  off  a  minute  branch  to  the  tympanum. 


NASAL    FOSSAE. 


To  expose  the  nasal  cavities,  the  saw  should  be  placed  at  the  side 
of  the  crista  galli,  and  carried  through  the  nasal  and  frontal  bones  to 
the  roof  of  the  mouth  ;  this  separates  the  portion  of  skull  iuto  two 
halves,  leaving  the  septum  nasi  attached  upon  one  side. 

The  two  cavities  on  either  side  of  the  septum  of  the  nose 
are  called  the  nasal  fossae;  they  communicate  with  the  pha- 
rynx and  face  by  apertures,  called  anterior  and  posterior 
mires,  and  also  with  the  sinuses  of  the  frontal,  ethmoid, 
sphenoid,  and  superior  maxillary  bones.  The  septum  of  the 
fossae  is  partly  osseous  and  partly  cartilaginous,  being 
formed  by  the  perpendicular  plate  of  the  ethmoid  bone,  the 
vomer,  and  the  triangular  cartilage  of  the  nose.  The  sep- 
tum is  usually  more  or  less  bent  to  one  or  the  other  side. 

On  the  outer  boundary  of  the  nasal  fossae  will  be  found 
the  three  convoluted  spongy  or  turbinated  bones.  The  two 
superior  are  processes  of  the  ethmoid  bone,  and  are  known 
respectively  as  the  superior  and  middle  turbinated  bones ; 
the  lower  one  is  an  independent  bone,  called  the  inferior 
turbinated  bone.  These  bones  overhang  spaces  called 
meatuses;  they  are  three  in  number;  the  superior  meatus 
is  the  smallest ;  it  is  overhung  by  the  superior  turbinated 
bone,  and  occupies  nearly  the  posterior  half  of  the  outer 
aspect  of  the  nasal  fossa ;  the  posterior  ethmoidal  sinuses 
open  into  it  in  front,  and  in  the  dried  bone  at  its  posterior 
part  will  be  found  the  spheno-palatine  foramen,  by  which 
the  nerves  and  vessels  enter  the  nose.  The  middle  turbi- 
nated bone  overhangs  the  middle  meatus,  which  extends 
nearty  the  whoie  length  of  the  outer  wall  of  the  fossa ;  it 

6* 


66  ANATOMY     OP    THE    HEAD     AND     NECK. 

communicates  anteriorly  with  the  frontal  sinuses  and  ant< 
rior  ethmoidal  cells,  and  near  its  middle  is  a  small  oblique 
aperture  the  size  of  a  crow-quill,  which  leads  to  the  cavity 
of  the   antrum.     The   inferior   meatus,  overhung  by  the 
inferior  turbinated  bone,  also  extends  the  whole  length  of 
the  nasal  fossa;  at  its  anterior  part  is  the  opening  of  the 
nasal  duct,  and  on  a  level  with  this,  but  more  posteriorly, 
the  Eustachian  tube,  which  connects  the  cavity  of  the  tym- 
panum with  the  pharynx,  may  be  seen. 

The  mucous  membrane  which  lines  the  fossae  and  mea- 
tuses  is  continuous  with  the  skin  anteriorly,  and  the 
pharyngeal  mucous  membrane  posteriorly,  and  is  called 
the  pituitary  or  Schneiderian  membrane. 


DISSECTION  X. 

TONGUE. 

The  TONGUE  is  made  up  of  muscular  fibres,  interspersed 
with  fat  and  cellular  tissue,  and  enveloped  by  mucous 
membrane.  It  is  separated  by  a  fibrous  septum  into  two 
lateral  halves,  and  is  attached  by  its  base  to  the  Ivyoid  bone  ; 
anteriorty  it  is  connected,  by  a  fold  of  mucous  membrane, 
called  the  frenum  linguae,  with  the  symphysis  of  the  lower 
jaw,  and  posteriorly  with  the  epiglottis,  by  a  central  and 
two  lateral  folds  of  mucous  membrane,  called  collectively 
the  glosso-epiglottidean  ligament ;  the  central  fold  is  called 
the  frenum  epigloltidix.  On  each  side  of  the  frenum  linguae 
is  a  papilla,  which  marks  the  orifice  of  the  duct  of  Wharton 
(p.  47).  On  each  side  of  the  frenum  there  is  also  a  promi- 
nence caused  by  the  sublingual  gland;  this  is  a  flattened 
and  elongated  conglomerate  gland,  similar  to  the  other 
salivary  glands,  but  smaller ;  it  pours  its  secretion  into  the 
mouth  by  numerous  small  orifices,  called  the  Eimnian 
ducts,  which  open  on  each  side  of  the  frenum. 

The  upper  surface  of  the  tongue  is  covered  with  numer- 
ous papillae,  called  from  their  shape  conical  and  filiform  ; 
the  latter  are  most  numerous  along  its  sides  ;  scattered 
among  these  are  a  few  more  prominent  papillae,  which  from 
being  larger  at  the  top  than  at  the  base  are  hence  called 
fungiform.  At  the  base  of  the  tongue,  arranged  across  it 
in  the  shape  of  the  letter  V,  are  eight  or  terf  papillae  called 


;; 


TONGUE.  67 

('(tliril'orm,  or  circun^vallatss  ;  they  are  pedunculated,  and 
surrounded  by  a  fold  of  mucous  membrane ;  at  the  apex  of 
the  two  rows  of  these  papillae  is  a  deep  mucous  follicle, 
called  the  foramen  csecum. 

Some  of  the  muscles  of  the  tongue  have  been  already  described  and 
divided;  their  lingual  ending  may  be  further  followed  out,  and  the 
intrinsic  muscles  dissected  by  removing  the  mucous  membrane;  to 
o  this  the  tongue  should  be  fixed,  by  large  pins  driven  through  it, 
the  table  on  which  it  lies. 


The  HYO-GLOSSUS  MUSCLE  arises  from  the  greater  and  lesser 
cornua  and  body  of  the  os  hyoides,  and  is  inserted  beneath 
the  stylo-glossns  into  the  sitle  of  the  tongue.  That  portion 
of  the  muscle  which  arises  from  the  body  of  the  hyoid  bone 
and  passes  obliquely  backward,  has  been  called  the  basio- 
glopsus ;  that  from  the  great  cornn  passes  forward,  which 
has  been  called  the  cerato-glossus  ;  while  a  few  fibres  from 
the  lesser  coruu,  spreading  along  the  side  of  the  tongue, 
have  been  named  the  chondro-glossus.  These  names  were 
applied  to  the  different  parts  of  the  muscle  by  Albinus. 
The  existence  of  the  chondro-glossus  is  disputed. 

Between  the  hyo-glossus  and  the  genio-hyo-glossus  mus- 
cles, and  connected  with  that  portion  of  the  hyo-glossus 
described  as  the  chondro-glossus,  is  a  bundle  of  fibres  run- 
ning longitudinally  from  the  base  to  the  apex  of  the  tongue ; 
this  is  called  the  inferior  lingualis  muscle.  The  superior 
linyiialis  muscle  is  a  thinner  and  less  distinct  band  of  fibres 
just  beneath  the  mucous  membrane  upon  thedorsum  of  the 
tongue,  arising  from  thefrenum  epiglottidis,  and  extending 
forward  to  its  apex. 

The  hyo-glossus  must  be  divided  at  its  hyoid  attachment,  and 
reflected,  in  order  to  expose  the  next  muscle. 

The  GENIO-HYO-GLOSSUS  MUSCLE  is  triangular  in  shape ; 
it  arises  from  the  symphysis  of  the  lower  jaw,  above  the 
genio-hyoid  muscle,  and  expanding  fan-shaped,  is  inserted 
into  the  whole  length  of  the  tongue  and  into  the  body  of 
the  hyoid  bone ;  by  making  a  longitudinal  section  of  the 
tongue  in  the  median  line,  the  direction  of  its  fibrae  will  be 
plainly  visible. 

A  section  thus  made  will  also  show  the  fibrous  septum 
which  separates  the  tongue  into  two  halves,  giving  to  it 
the  character  of  duality  which  belongs  to  all  the  special 
senses;  although  rudimentary  in  the  human  species,  this 


68  ANATOMY     OF    THE     HEAD     AND     NECK. 

separation  into  two  parts  is  marked  in  the  tongues  of  cer- 
tain birds  and  reptiles. 

The  lingual  artery  will  be  found  resting  upon  the  genio- 
hyo-glossus  muscle;  it  gives  a  branch  to  the  dorsum  of  the 
tongue,  and  is  continued  forward  to  its  apex  under  the 
name  of  the  ranine  artery. 

Upon  the  hyo-glossus  muscle  the  gustatory  nerve  will  be 
seen ;  this  is  a  branch  of  the  inferior  maxillary  trunk  of 
the  fifth  nerve;  it  anastomoses  with  small  branches  of  the 
hypoglossal,  and  is  distributed  to  the  mucous  membrane 
and  papillae  of  the  tongue. 

The  hypoglossal  nerve  also  crosses  the  hyo-glossus  muscle, 
and,  after  penetrating  the  genio-hyo-glossus,  is  continued 
forward  to  the  apex  of  the  tongue  in  the  substance  of  that 
muscle.  It  supplies  the  muscular  structure  of  the  tongue. 

The  glosso-pharyngeal  nerve  passes  under  the  posterior 
border  of  the  Iryoglossus  muscle,  and  supplies  the  dorsum 
and  lateral  mucous  membrane  of  the  tongue,  the  tonsils, 
and  the  fauces. 

LARYNX. 

The  tongue  should  now  be  separated  from  the  larynx  without 
injuring  the  epiglottis;  the  hyoid  bone  should  remain  attached  to 
the  larynx.  The  larynx  should  be  extended,  and  made  fast  to  the 
table  by  means  of  pins  ;  the  pharynx  and  extrinsic  muscles  should 
be  dissected  away  from  its  cartilages  and  from  the  hyoid  bone. 

The  hyoid  bone  is  connected  with  the  thyroid  cartilage 
of  the  larynx  by  a  membrane  called  the  thyro-hyoid  mem- 
brane, which  includes  the  entire  space  intervening  between 
the  upper  border  of  the  thyroid  cartilage  and  the  upper 
border  of  the  hyoid  bone;  this  membrane  is  perforated  by 
the  superior  laryngeal  nerve  and  the  superior  laryngeal 
artery. 

The  CRICO-THYROIDEUS  MUSCLE  is  a  triangular  muscle, 
and  the  largest  of  the  special  muscles  of  the  larynx ;  it 
arises  from  the  front  and  lateral  part  of  the  cricoid  car- 
tilage, and  passes  outward  and  backward,  to  be  inserted 
into  the  external  and  internal  surfaces  of  the  lower  border 
of  the  tnVroicl  cartilage. 

The  CRICO-ARYTENOIDEUS  POSTTCUS  MUSCLE  arises  from 
the  depression  on  the  side  of  the  vertical  ridge  of  the  cricoid 
cartilage  posteriorly ;  its  fibres  converge  and  are  inserted 
into  the  muscular  process  of  the  arytenoid  cartilage. 

The  ARYTENOIDEUS  MUSCLE  covers  in  and  unites  the  pos- 


» 


LARYNX.  69 

terior  surfaces  of  the  two  aiytenoid  cartilages ;  the  fibres  of 
this  muscle  consist  of  fasciculi,  having  partly  a  horizontal 
or  transverse,  and  partly  an  oblique  direction. 

To  expose  the  remaining  muscles  of  the  larynx,  one  side  of  the 
thyroid  cartilage  must  be  removed. 

The  CRICO-ARYTENOIDEUS  LATERALIS  MUSCLE  arises  from 

e  lateral  part  of  the  upper  border  of  the  cricoid  cartilage, 
and  is  inserted  into  the  muscular  process  of  the  arytenoid 
cartilage. 

The  THYRO-ARYTENOIDEUS  MUSCLE  arises  from  the  angle 
of  the  thyroid  cartilage  and  is  a  complex  muscle,  imper- 
fectly demonstrable  in  an  ordinary  dissection.  One  por- 
tion, quadrangular  in  shape,  passes  backward  to  be  inserted 
into  the  vocal  process  of  the  arytenoid  cartilage,  and  forms 
the  lower  surface  of  the  vocal  cord.  A  second  portion  also 
runs  backward  and  is  inserted  into  the  lower  part  of  the 
antero-external  surface  of  the  aiytenoid  cartilage,  helping 
to  form  the  lower  wall  of  the  ventricle  of  the  larynx.  A 
third  portion  sends  its  fibres  in  different  directions ;  some 
pass  backward  to  the  lower  part  of  the  outer  edge  of  the 
arytenoid  cartilage ;  others  passing  along  the  outer  wall  of 
the  ventricle  of  the  larynx  lose  themselves  in  the  ary-epi- 
glottidean  fold ;  others  again  pass  partly  into  the  ventricu- 
lar cord  and  partly  up  to  the  epiglottis. 

The  cavity  of  the  larynx  is  divided  into  two  parts  by  a 
constriction  caused  by  the  prominence  of  two  elastic  fibrous 
ligaments,  attached  in  front  to  the  angle  of  the  thyroid  car- 
tilage, and  posteriorly  to  the  bases  of  the  arytenoid  car- 
tilages. These  are  called  the  vocal  cords,  and  the  space 
between  them  is  called  the  rima  glottidis.  Immediately 
above  and  running  parallel  with  the  vocal  cords  are  two 
folds  of  mucous  membrane  called  the  false  cords,  or,  more 
properly,  the  ventricular  cords  or  bands.  The  space  be- 
tween the  vocal  cords  and  the  ventricular  bands  is  called 
the  ventricle  of  the  larynx. 

In  the  ventricle  of  the  larynx  the  mucous  membrane 
forms  a  deep  pouch,  best  demonstrated  by  stuffing  it  with 
cotton-wool ;  this  is  called  the  sacculus  laryngis,  and  is 
directed  upward,  sometimes  as  high  as  the  upper  border  of 
the  thyroid  cartilage. 

The  lateral  boundaries  of  the  upper  laryngeal  aperture 
are  formed  by  folds  of  mucous  membrane,  called  the  ary- 
epiglottidean  folds,  which  pass  from  the  sides  of  the  epi- 


70  ANATOMY     OF     THE     HEAD     AND     NECK. 

glottis,  backward,  downward,  and  inward,  in  a  semi-circular 
form,  toward  each  other.  In  these  folds,  posteriorly,  are 
found  the  cartilages  of  Wrisberg,  and  the  cartilages  of 
Santorini. 

The  larynx  is  supplied  with  nerves  from  the  superior  and 
inferior  laryngeal  branches  of  the  pneuinogastric  nerve. 
The  superior  laryngeal  penetrates  the  thyro-hyoid  mem- 
brane, and  supplies  the  mucous  membrane  and  crico-thyroid 
muscle.  The  inferior  or  recurrent  laryngeal  nerve  passes 
beneath  the  ala  of  the  thyroid  cartilage,  and  supplies  all  the 
special  muscles  of  the  larynx  except  the  crico-thyroid. 

These  nerves  are  accompanied  by  the  laryngeal  branches 
of  the  superior  and  inferior  thyroid  arteries,  which  follow 
them  in  their  distribution  to  the  mucous  membrane  and 
muscles. 

The  hyoid  bone  and  the  cartilages  of  the  larynx  are  now  to  be  de- 
nuded, care  being  taken  to  leave  the  ligaments  which  unite  the  dif- 
ferent cartilages,  as  well  as  the  membrane  between  the  larynx  and 
hyoid  bone. 

The  HYOID  BONE  consists  of  a  body  and  four  cornua,  two 
greater  and  two  lesser.  The  greater  cornu  extends  back- 
ward, decreasing  gradually  in  size,  and  ends  posteriorly  in 
a  tubercle ;  the  lesser  cornu  is  directed  upward,  and  is 
about  the  size  and  shape  of  a  kernel  of  rice ;  it  marks  the 
union  of  the  body  of  the  bone  with  the  greater  cornu,  and 
is  seldom  co-ossified  with  it;  the  stylo-hyoid  ligament  is 
attached  to  it.  (p.  51.) 

The  THYROID  CARTILAGE  of  the  larynx  consists  of  two 
quadrilateral  halves  united  anteriorly  at  an  acute  angle, 
forming  a  projection  called  the  pomum  Adami.  The  upper 
border,  above  the  pomum  Adami  has  a  deep  notch  called 
incisura  thyroidese  superior;  the  lower  border  has  a 
slighter  notch  called  incisura  thyroidese  inferior.  Poste- 
riorly the  cartilage  has  a  thick  border,  which  terminates 
above  and  below  in  a  cornu ;  the  upper  being  the  longest, 
and  the  lower  the  stoutest.  The  upper  cornu  is  connected 
to  the  greater  cornu  of  the  hyoid  bone  by  a  ligament,  called 
the  thyro-hyoid;  a  sesamoid  bone,  or  cartilage,  is  usually 
found  in  it.  The  lower  cornu  articulates  with  the  cricoid 
cartilage.  The  inner  surface  of  this  cartilage  is  smooth, 
the  outer  is  marked  by  an  oblique  ridge,  extending  from  its 
upper  cornu  to  the  middle  of  the  lower  border. 


LARYNX.  71 

This  cartilage  is  connected  to  the  cricoid  cartilage  by  a 
membrane  called  the  crico-thyroid. 

The  CRICOID  CARTILAGE  forms  a  complete  ring,  and  is 
thicker  than  the  thj-roid ;  it  is  broader  behind  than  in  front, 
and  resembles  somewhat  in  its  shape  a  signet  ring;  the 
inner  surface  is  smooth,  the  outer  is  rough  for  the  attach- 
ment of  muscles ;  the  lower  border  is  straight,  and  united 
by  a  fibrous  membrane  with  the  first  ring  of  the  trachea; 
the  upper  border  is  irregular. 

The  ARYTENOID  CARTILAGES  are  two  in  number,  one  on 
each  side,  and  are  placed  on  the  upper  border  of  the  cricoid 
cartilage  at  the  back  of  the  larynx ;  they  are  pyramidal  in 
shape,  having  a  base  and  three  surfaces ;  at  the  lower  part 
there  is  externally  a  short  process  called  the  muscular  pro- 
cess, and  anteriorly  a  longer  pointed  process,  the  vocal 
process.  Attached  to  the  apex  of  each  cartilage  is  a  small 
fibrous  body,  called  the  cartilage  of  Santorini. 

The  CUNEIFORM  CARTILAGES,  or  CARTILAGES  OF  WRIS- 
BERG,  are  attached  to  the  middle  of  the  external  surface  of 
the  arytenoid  cartilages  ;  they  are  sometimes  wanting. 

The  EPIGLOTTIS  is  composed  of  yellow  elastic  fibre,  and 
resembles  in  shape  a  rounded  leaf  with  the  stalk  down- 
ward ;  it  is  often  indented  in  the  middle  of  its  free  edge 
and  rolled  in  from  the  sides;  it  is  connected  with  the 
tongue  by  a  central  and  two  lateral  folds  of  mucous  mem- 
brane, known  as  the  glosso-epiglottidean  ligament ;  the  cen- 
tral fold  is  called  the  frenum  epiglottidis.  A  fibrous  band, 
called  the  thyro-epiglottic  ligament,  unites  the  epiglottis  to 
the  notch  in  the  anterior  border  of  the  thyroid  cartilage 
below;  it  is  also  connected  with  the  hyoid  bone  by  strong 
bands  of  fibrous  tissue  called  the  hyo-epiglottic  ligament. 
Between  the  epiglottis  and  the  hyoid  bone  is  a  mass  of 
yellowish  fat,  which  has  been  improperly  named  the  epi- 
gloftidean  gland. 

The  TRACHEA  is  composed  of  from  sixteen  to  twenty  in- 
complete cartilaginous  rings,  each  forming  about  three- 
fourths  of  a  circle ;  some  of  them  blend  together,  but  for 
the  most  part  they  are  united  by  a  fibrous  tissue,  extending 
across  between  their  ends  and  forming  a  flattened  wall 
which  completes  the  tube.  The  posterior  wall  of  the  trachea, 
in  addition  to  this  fibrous  membrane,  has  a  layer  of  muscu- 
lar tissue  closely  connected  with  the  mucous  membrane, 
and  its  surface  is  dotted  with  well-marked  muciparous 


72      ANATOMY  OF  THE  HEAD  AND  NECK 

glands.     The  continuation  of  the  trachea  is  described  in 
connection  with  the  lungs. 


DISSECTION  XL 

PREVERTEBRAL    REGION. 

The  dissection  now  reverts  to  that  portion  of  the  vertebral  column 
put  aside  after  the  separation  of  the  pharynx,  viz.,  the  prevertebral 
region.  The  removal  of  a  small  amount  of  cellular  tissue  exposes 
several  muscles  ;  the  superior  of  which,  the  rectus  capitis  anticus 
major  and  minor,  are  usually  found  mutilated  by  the  cutting  through 
of  the  occipital  bone. 

The  RECTUS  CAPITIS  ANTICUS  MAJOR  MUSCLE,  superiorly 
the  most  superficial  of  the  prevertebral  muscles,  arises  by 
tendinous  slips  from  the  anterior  tubercles  of  the  trans- 
verse processes  of  the  third,  fourth,  fifth,  and  sixth  cervical 
vertebrae;  these  unite  to  form  a  single  belly,  and  the  mus- 
cle is  inserted  into  the  basilar  process  of  the  occipital 
bone. 

The  LONGUS  COLLI  MUSCLE,  partly  concealed  by  the  pre- 
ceding, is,  however,  superficial  at  its  lower  part,  where  it 
lies  upon  the  bodies  of  the  vertebrae.  This  muscle  is 
pointed  above  and  broad  below,  and  consists  of  an  external 
and  an  internal  part,  the  former  being  vertical,  and  the 
latter  oblique.  The  internal  part  arises  by  fleshy  and  tendin- 
ous processes  from  the  bodies  of  the  two  upper  dorsal  and 
two  lower  cervical  vertebrae ;  the  external  part  arises  from 
the  anterior  tubercles  of  the  transverse  processes  of  the 
third,  fourth,  fifth,  and  sixth  cervical  vertebrae;  the  two 
portions  then  blend  together,  and  are  inserted  by  four  slips 
into  the  lower  border  of  the  bodies  of  the  four  upper  cer- 
vical vertebrae ;  some  of  the  most  external  fibres  of  the  lower 
part  of  this  muscle  are  occasionally  attached  by  separate 
tendons  to  the  transverse  processes  of  the  lower  cervical 
vertebrae. 

The  RECTUS  CAPITIS  ANTICUS  MINOR  MUSCLE  lies  beneath 
the  rectus  anticus  major,  which  must  therefore  be  removed; 
it  arises  from  the  anterior  border  of  the  lateral  half  of  the 
atlas,  and  is  inserted  into  the  basilar  process  of  the  occipital 
bone. 

The  RECTUS  CAPITIS  LATERALIS  MUSCLE  arises  from  the 


PRE VERTEBRAL    REGION.  73 

transverse  process  of  the  atlas,  and  is  inserted  into  the 
rough  surface  of  the  occipital  bone  external  to  its  condyle. 

The  SCALENUS  ANTICUS  MUSCLE  arises  from  the  anterior 
tubercles  of  the  transverse  processes  of  the  third,  fourth, 
flh,  and  sixth  cervical  vertebrae,  and  is  inserted  into  a 
ubercle  on  the  upper  surface  of  the  first  rib ;  this  tubercle 

important  to  notice,  since  it  may  be  felt  by  the  finger  in 

arching  for  the  subclavian  artery  when  that  vessel  is  to 

tied,  and  the  artery  lies  directly  behind  this  insertion  of 
muscle.  The  vertebral  origin,  it  will  be  observed,- 
corresponds  with  that  of  the  rectus  anticus  major  muscle, 
of  which  it  may  in  some  sort  be  considered  the  continua- 
tion. 

The  SCALENUS  MEDIUS  MUSCLE  arises  from  the  posterior 
tubercles  of  the  transverse  processes  of  all  the  cervical 
vertebrae,  except  the  first,  and  is  inserted  by  two  fleshy 
bellies  into  the  first  and  second  ribs,  the  one  inserted  into 
the  second  being  smaller  than  that  into  the  first  rib ;  the 
attachment  to  the  second  rib  is  often  described  as  a  separate 
muscle,  under  the  name  of  scalenus  posticus. 

Between  the  anterior  tubercles  of  the  transverse  pro- 
cesses of  the  cervical  vertebrae,  are  the  anterior  pairs  of 
the  inter-transversales  muscles,  the  first  pair  being  between 
the  atlas  and  axis,  and  the  last  between  the  last  cervical 
and  first  dorsal  vertebrae.  The  lower  anterior  inter-trans- 
versalis  muscle  is  often  wanting.  Between  the  pairs,  ex- 
cept in  the  first  two  spaces,  the  anterior  primary  branch  of 
the  cervical  nerves  makes  its  exit ;  beneath .  the  posterior 
muscle  the  posterior  primary  branch  of  the  same  nerve 
emerges. 

The  anterior  division  of  the  first  spinal  or  sub-occipital 
nerve,  is  given  off  from  the  common  trunk  while  the  latter 
lies  upon  the  posterior  arch  of  the  atlas ;  it  then  curves 
downward  in  front  of  the  transverse  process  of  the  atlas, 
and  forms  a  loop  of  communication  with  an  ascending 
branch  of  the  second  cervical  nerve;  it  supplies  the  rectus 
lateralis  and  rectus  anticus  minor,  and  communicates  with 
the  pneumogastric,  hypoglossal,  and  sympathetic  nerves. 

The  anterior  division  of  the  second  cervical  nerve  passes 
over  the  lamina  of  the  axis,  is  directed  forward,  outside  the 
vertebral  artery,  and  beneath  the  inter-tracsversalis  muscle 
of  the  first  space,  to  join  the  cervical  plexus. 

The  vertebral  artery,  already  described  at  p.  58,  may  be 
further  examined,  by  removing  the  inter-transversales  mus- 


74  ANATOMY    OF    THE     HEAD'   AND     NECK. 

cles;  it  will  then  be  seen  lying  in  the  canal  of  the  trans 
verse  processes  of  all  the  cervical  vertebrae,  except  th< 
seventh;  after  emerging  from  the  atlas,  it  winds  round  ii 
articular   process,   and,   piercing  the   posterior    occipit< 
atloid  ligament  as  well  as  the  dura  mater,  enters  the  fora- 
men magnum.     Its  small  offsets  to  the  spinal  membranes 
can  now  be  seen  at  their  origin. 

LIGAMENTS    OF    THE    FIRST    TWO    VERTEBRA. 

The  cervical  vertebrae  are  connected  with  each  other  by 
ligaments  similar  to  those  of  the  rest  of  the  vertebrae, 
which  are  described  in  Part  Second,  Dissection  X.  The 
two  upper  vertebrae  are,  however,  connected  by  special 
ligaments  with  each  other,  and  with  the  occipital  bone. 

•  The  removal  of  all  the  muscles,  and  other  extraneous  tissues  about 
the  base  of  the  skull  and  the  upper  part  of  the  vertebral  column,  will 
be  necessary  to  expose  these  articulations. 

The  OCCIPITO-ATLOID  ARTICULATION  is  maintained  by 
two  ligaments.  The  anterior  occipito-atloid  ligament  con- 
sists of  a  rounded  cord  attached  above  to  the  basilar  pro- 
cess of  the  occipital  bone,  and  below  to  the  anterior 
tubercle  of  the  atlas ;  beneath  this  is  a  broad  membrane, 
extending  from  the  anterior  margin  of  the  foramen  mag- 
num to  the  anterior  arch  of  the  atlas ;  this  latter  is  some- 
times described  separately  as  the  deep  anterior  ligament. 
The  posterior  occipito-atloid  ligament  extends  from  the  pos- 
terior margin  of  the  foramen  magnum  to  the  posterior  arch 
of  the  atlas ;  it  is  perforated  by  the  vertebral  arteries  and 
by  the  sub-occipital  nerve.  Lateral  ligaments,  consisting  of 
stout  fibrous  bands,  extend  from  the  bases  of  the  transverse 
processes  of  the  atlas  to  the  jugular  processes  of  the  occi- 
pital bone ;  capsular  ligaments  surround  the  articulation  of 
the  condyles  of  the  occipital  bone  with  the  articulating  sur- 
faces of  the  atlas,  and  the  articulation  of  the  atlas  and  axis 
is  similarly  provided. 

The  ATLO-AXOIDEAN  ARTICULATION  is  maintained  exter- 
nally by  a  thin  membrane,  which  unites  the  bodies  of  the 
atlas  and  axis  anteriorly,  and  their  arches  posteriorly. 

To  see  the  ligaments  inside  the  spinal  canal,  the  posterior  arches  of 
the  atlas  and  axis  must  be  cut  away,  as  well  as  the  occipital  bone  so 
far  as  it  forms  the  posterior  half  of  the  foramen  magnum  ;  the  dura 
mater  is  to  be  removed. 


LIGAMENTS    OF     THE    FIRST     TWO    VERTEBRA.       75 

The  ligaments  constituting  the  OCCIPITO-AXOIDEAN  ARTI- 
CULATION are  peculiar  in  arrangement,  and  maintain  the 
relation  of  the  bones  during  rotatory  and  nodding  move- 
ments. 

The  occipito-axoid  ligament,  or  the  apparatus  ligamento- 
colli,  is  attached  above  by  a  broad  expansion  to  the 
isilar  process  of  the  occipital  bone,  in  front  of  the  fora- 
icn  magnum ;  below  it  is  continuous  with  the  posterior 
common    ligament    of  the    vertebral    column ;    its    deeper 
>res,  however,  have  a  special  insertion  into  the  posterior 
irt  of  the  body  of  the  axis,  and  into  the  superior  border 
>f  the  transverse  ligament. 

The  occipito-axoid  ligament  is  to  be  removed  in  such  a  way  as  to 
leave  the  portion  which  is  inserted  into  the  transverse  ligament. 

The  odontoid  ligaments  are  two  strong  bands  extending 
from  the  sides  of  the  apex  of  the  odontoid  process  to  a 
depression  on  the  inner  surface  of  the  condyles  of  the  occi- 
pital bone.  A  third  band  extends  from  the  tip  of  the  odon- 
toid process  to  the  anterior  edge  of  the  foramen  magnum  ; 
it  bears  the  name  of  ligamentum  suspensorium.  As  these 
ligaments  control  the  movements  of  the  cranium  in  rotation 
they  are  sometimes  called  the  check  ligaments. 

The  transverse  ligament  extends  across  the  odontoid 
process  from  a  tubercle  on  the  inner  surface  of  one  articu- 
lar process  of  the  atlas  to  a  similar  point  on  the  other ;  its 
upper  border  receives  a  part  of  the  occipito-axoid  ligament, 
and  its  inferior  border  sends  some  fibres  downward  to  the 
base  of  the  odontoid  process ;  from  this  arrangement  of  its 
fibres  it  is  sometimes  called  the  crucial  ligament. 

The  removal  of  the  odontoid  and  transverse  ligaments 
will  show  an  articulating  surface  in  front  of  the  odontoid 
process,  where  it  rests  against  the  atlas,  and  another  be-' 
hind,  where  it  comes  in  contact  with  the  transverse  liga- 
ment ;  these  are  both  provided  with  synovial  membranes. 


DISSECTION  XII. 

ANATOMY    OF    THE    EYE. 

The  structure  of  the  eye  is  best  studied  upon  that  of  some  animal. 
The  market-house  will  almost  always  furnish  those  of  an  ox,  calf,  or 


70  ANATOMY     OF     THE     HEAD     AND     NECK. 

sheep.  A  number  of  them  is  desirable,  and  their  dissection  should  lx 
conducted  in  water.  A  soup-plate  is  a  convenient  dish  for  this  pur- 
pose. The  muscles  and  the  mucous  membrane  should  all  be  remove  " 
and  the  eyeball  left  with  the  optic  nerve  alone  attached  to  it.  In  ordei 
to  obtain  a  general  idea  of  the  different  parts,  the  student  will  do  well 
to  make  botli  a  longitudinal  and  a  transverse  section  of  the  eyeball,  an< 
this  he  will  easily  accomplish  if  he  will  first  freeze  the  eye  by  immers- 
ing it  in  a  mixture  of  ice  and  salt. 

The  ORGAN  OF  VISION  is  composed  of  certain  parts  essen- 
tial to  sight  and  of  others  requisite  for  their  protection. 
Its  sentient  constituent  is  an  expansion  of  the  optic  nerve 
(retina).  A  series  of  transparent  parts  (cornea,  lens,  vitre- 
ous humor)  bring  the  rays  of  light  to  a  focus  upon  the 
retina ;  and  a  movable  curtain  (iris)  regulates  the  extent  of 
their  admission.  To  defend  these  structures,  a  dense  tunic 
(sclerotic)  is  arranged  around  them,  and  to  absorb  the 
superabundant  rays  of  light  there  is  an  internal  tunic  (cho- 
roicl)  provided  with  a  layer  of  pigment. 

The  SCLEROTIC  TUNIC  extends  from  the  entrance  of  the 
optic  nerve  to  the  cornea,  and  forms  five-sixths  of  the  sur- 
face of  the  eyeball.  The  optic  nerve  perforates  it  a  little 
to  the  inner  side  of  its  centre ;  a  marked  constrictioi 
characterizes  it  just  previous  to  its  entrance;  if  the  nerve 
be  drawn  out,  it  will  be  seen  that  it  leaves  an  orifice  in  the 
sclerotic,  tapering  inward,  and  which  at  the  bottom  is  pei 
forated  by  minute  holes,  through  which  the  fibres  of  th< 
nerve  penetrated;  this  spot  has  hence  been  called  the  lamim 
cribrosa.  The  inner  aspect  of  the  sclerotic  is  flocculent  witl 
the  ends  of  ruptured  vessels  and  nerves ;  externally  it  it 
smooth  except  where  muscles  are  attached,  and  it  is  thickest 
at  the  posterior  part. 

The  CORNEA  is  a  clear  and  diaphanous  structure  whicl 
forms  the  anterior  wall  of  the  anterior  chamber  of  the  ey( 
and  admits  the  rays  of  light.  It  is  circular  in  form,  and, 
like  the  crystal  of  a  watch,  is  convex  anteriorly  and 
cave  posteriorly;  at  its  circumference  it  blends  with  the 
sclerotic  by  continuity  of  tissue ;  its  structure  is  laminated, 
and  it  is  covered  superficially  by  the  conjunctiva  (p.  17) ;  il 
internal  surface  is  lined  by  a  structureless  membrane,  called 
the  membrane  of  Descemet  or  of  Demours.  In  its  health; 
state  the  cornea  is  devoid  of  vessels ;  after  death  it  become 
flaccid  and  opaque  from  infiltration  of  the  aqueous  humor. 

The  vascular  coat  of  the  eyeball  is  internal  to  the  scl< 
rotic;  it  is  a  thin  membrane  made  up  of  bloodvessels  an< 
pigment  cells,  divisible  into  three  parts :  a  posterior  poi 


TIIEEYE.  77 

tiou,  corresponding  to  the  sclerotic,  and  which  is  called  the 
choroid ;  an  anterior  portion  opposite  the  cornea,  called 
the  iris ;  and  an  intermediate  ring  on  a  level  with  the  union 
of  the  sclerotic  and  cornea,  consisting  of  the  ciliary  muscle 
and  processes. 

To  show  the  choroid,  the  sclerotic  is  to  be  cut  through  just  behind 
the  cornea,  and  from  this  circular  incision  three  or  four  slits  are  to  be 
made  with  the  scissors  toward  the  optic  nerve;  the  resulting  flaps 
are  then  to  be  carefully  reflected.  In  another  eye  the  cornea  should 
be  removed  and  the  iris  gently  torn  away  with  the  forceps  ;  this  will 
expose  the  ciliary  processes. 

The  CHOROID  is  a  thin  pigmentary  membrane,  extending 
from  the  optic  nerve,  which  perforates  it,  to  the  anterior 
part  of  the  eyeball,  as  far  forward  as  a  white  ring  at  the 
line  of  union  between  the  sclerotic  and  cornea,  which  is  the 
ciliary  muscle  ;  at  this  point  the  choroid  bends  inward 
behind  the  iris  to  end  in  a  series  of  plaited  folds,  called 
the  cilia ry  processes^  arranged  around  the  lens  in  the  form 
of  a  circle.  The  pigment  of  the  choroid  is  principally  con- 
tained in  an  internal  epithelial  layer,  and  is  easily  detached 
and  washed  away.  In  many  animals,  at  the  bottom  of  the 
eye,  there  is  a  brilliant  arrangement  of  fibres  on  the  internal 
surface  of  the  choroid,  which  shines  with  a  metallic  lustre, 
and  is  called  the  tapetum  oculi. 

The  CILIARY  LIGAMENT,  or,  as  it  is  now  more  properly 
termed,  the  CILIARY  MUSCLE,  will  be  seen  as  a  white  ring 
sometimes  called  the  armulus  albidus,  situated  outside  that 
part  of  the  choroid  which  turns  inward  to  form  the  ciliary 
processes,  and  opposite  the  junction  of  the  cornea  and  scle- 
rotic coats.  The  ciliary  muscle  constitutes  the  most  anterior 
part  of  the  choroid;  its  muscular  character  is  not  capable 
of  demonstration  in  an  ordinary  dissection,  but  it  fulfils 
an  important  office  in  connection  with  the  sense  of  vision. 
Between  the  ciliary  muscle  and  the  sclerotic  is  a  minute 
vascular  canal  called  the  canal  of  Schlemm,  sometimes  also 
of  Font  ana. 

The  IRIS  is  a  vascular  and  muscular  structure,  sufficiently 
displayed  in  the  dissections  already  made;  it  is  circular  in 
form,  and  is  suspended  vertically  in  front  of  the  crystalline 
lens ;  its  anterior  surface  is  free  in  the  aqueous  humor,  and 
marked  by  lines  converging  toward  the  pupil;  its  posterior 
surface  is  covered  by  a  thick  la}^er  of  pigment,  to  which 
the  name  uvea  has  been  applied,  and  is  in  contact  with 
the  lens ;  its  circumference  corresponds  to  the  point  at 

7* 


78      ANATOMY  OF  THE  HEAD  AND  NECK. 

which  the  sclerotic  and  cornea  blend,  and  it  is  connectec 
with  the  choroid  by  means  of  the  ciliary  muscle.  Th< 
muscular  fibres  of  the  iris  are  unstriated,  and  are  botl 
circular  and  radiating. 

The  CHAMBERS  OF  THE  AQUEOUS  HUMOR  are  the  spac( 
between  the  lens  behind  and  the  cornea  in  front,  separate 
by  the  iris  into  two  compartments,  anterior  and  posterior 
The  anterior  chamber  is  the  larger  of  the  two ;  their  bound: 
ries  will  be  best  seen  in  an  e}7e  that  is  bisected  longitudi- 
nally.    The  aqueous  humor  is  a  pure  transparent  fluid;  il 
disappears  by  transudation  a  short  time  after  death. 

The  NERVOUS  COAT,  or  the  RETINA,  requires  to  be  dis- 
sected in  a  recent  eye;  it  is  the  most  internal  of  the  three 
coats  of  the  eyeball  and  one  of  the  most  delicate  of  its 
structures ;  it  lies  between  the  choroid  and  the  vitreous 
humor,  upon  which  it  is  moulded. 

The  retina  may  be  seen  by  gently  tearing  away  the  choroid  in  the  eye 
that  was  used  for  the  examination  of  that  membrane,  or  by  emptying 
an  eye  of  its  vitreous  humor  after  the  removal  of  an  anterior  segment. 

The  retina  expands  as  far  forward  as  the  outer  edge  of 
the  ciliary  processes,  where  it  forms  a  scolloped  border, 
called  the  ora  serrata,  and  may  be  traced  backward  to  the 
lamina  cribrosa,  the  point  at  which  the  optic  nerve  enters 
the  eyeball ;  a  thin  hyaloid  membrane,  called  the  zonula 
ciliaris,  or  zone  of  Zinn,  is  attached  to  the  anterior  border 
of  the  retina,  and  continued  to  the  anterior  surface  of  the 
lens.  This  membrane,  which  is  composed  of  folds  into 
which  the  ciliary  processes  fit,  becomes  stained  with  their 
pigment,  so  as  to  leave  a  series  of  radiating  lines  around 
the  lens.  On  looking  through  the  vitreous  body,  the  cen- 
tral artery  of  the  retina  wsiy  be  seen  entering  b}^  a  central 
foramen  in  the  lamina  cribrosa  called  the  porus  opticus. 
A  circular  spot  at  the  posterior  part  of  the  retina  is 
called  the  foramen  of  Soemmering;  and  this  is  surrounded 
by  a  yellow  halo  called  the  limbus  luteus. 

The  CRYSTALLINE  LENS  lies  in  a  depression  in  the  front  of 
the  vitreous  humor,  and  behind  the  pupil  of  the  iris.  It 
has  a  proper  capsule  of  transparent  membrane,  and  is  held 
in  its  place  by  a  suspensory  ligament,  which  is  formed 
by  the  zonula  ciliaris  in  front  and  by  a  similar  hyaloid 
membrane  posteriorly,  the  two  uniting  behind  the  ciliary 
processes;  the  space  between  these  two  layers  is  called  the 
canal  of  Petit;  this  may  be  demonstrated  by  the  blow-pipe, 


ENCEPIIALON.  19 

and  the  inflation  of  the  folds  in  the  anterior  membrane 
gives  the  canal  a  beaded  appearance  when  distended.  The 
lens  itself  is  a  transparent  double  convex  body,  the  poste- 
rior convexity  being  greater  than  the  anterior:  its  consist- 
ency is  greater  at  the  centre  or  nucleus  than  it  is  externally. 
By  allowing  it  to  lie  in  water  for  a  little  while,  each  surface 
will  separate  into  three  parts  by  lines  radiating  from  the 
mtre,  those  of  one  side  being  intermediate  in  position  to 
lose  of  the  other.  If  the  lens  be  hardened  either  in  alco- 
)1  or  by  boiling,  it  will  be  easy  to  separate  it  into  laminae, 
like  those  of  an  onion,  each  lamina  being  divided  into  three 
segments  by  the  diverging  lines,  just  spoken  of. 

The  VITREOUS  HUMOR  is  a  jelly-like,  transparent  sub- 
stance, filling  the  greater  part  of  the  eyeball  behind  the 
iris ;  it  is  contained  in  a  thin  and  delicate  membrane  called 
the  hyaloid,  which  not  only  envelops  it  externally,  but  pene- 
trates into  its  interior,  and,  forming  a  sort  of  trabeculated 
arrangement,  helps  to  support  it  and  retain  it  in  place. 


DISSECTION  XIII. 

ANATOMY    OF   THE    ENCEPHALON. 


The  density  of  the  cerehral  substance  increasing  with  age,  the  brains 
of  persons  advanced  in  life  are  the  most  desirable  for  examination. 
The  autopsy-room  is  the  only,  place  where  they  can  be  obtained  fresh 
enough  for  dissection,  and  the  firmness  of  their  tissue  may  be  improved 
by  several  days'  immersion  in  alcohol.  For  inspection,  the  brain  is 
to  be  placed  with  its  base  uppermost,  and  with  its  convexity  resting 
in  a  coil  of  cloth,  to  maintain  it  in  position. 

MEMBRANES   AND    VESSELS. 

The  dura  mater  has  been  previously  described  (Dissec- 
tion IV.);  the  arachnoid  and  pia  mater  are  still  connected 
with  the  brain  after  its  removal ;  all  of  these  membranes' 
are  prolonged  into  the  vertebral  canal,  and  can  be  seen  in 
dissecting  the  spinal  cord. 

The  ARACHNOID,  a  thin  serous  membrane,  the  parietal  part 
of  which  has  been  already  observed  lining  the  inner  surface 
of  the  dura  mater,  is  reflected  over  the  pia  mater,  and  may 
be  demonstrated  at  almost  any  point  where  it  passes  across 
the  intervals  between  one  convolution  of  the  brain  and 


SO  ANATOMY    OF    THE     HEAD    AND    NECK. 

another.     It  covers  the  encephalon  loosely,  and  leaves 
considerable  space  between  it  and  the  convolutions;  thi 
space,  called  the  sub-arachnoid,  is  greatest  at  the  base 
the  brain,  and  here  as  elsewhere  contains  more  or  less  fluid, 
which,  from  the  continuity  existing  between  the  snb-aracl 
noid  space  of  the  cranium  and  that  of  the  spinal  canal, 
called  the  cerebro-spinal  fluid.    The  cerebro-spinal  fluid 
however,  often  lost  in  the  course  of  dissection,  from  wound- 
ing a  dependent  portion  of  the  membrane,  through  whi< 
it  drains  off  from  both  the  cerebral  and  spinal  spaces. 

The  PIA  MATER  is  the  vascular  covering  of  the  brain, 
and  this,  likewise,  envelops  both  the  encephalon  and  spins 
cord  ;  it  is  in  close  contact  with  the  cerebral  substance,  an< 
dips  into  the  fissures  and  convolutions  ;  it  also  penetrates 
into  the  interior  of  the  brain,  to  supply  vessels  to  the  walls 
of  the  cavities  there  existing. 

In  connection  with  the  membranes  will  be  found  th< 
arteries  of  the  brain,  derived  from  the  vertebral  and  inter- 
nal carotid  arteries. 

The  vertebral  artery  (p.  58)  supplies  the  cerebellum  an< 
posterior  lobes  of  the  cerebrum  ;  it  ascends  by  the  side  of 
the  medulla  oblongata,  and  at  the  posterior  border  of  the 
poris  Yarolii  unites  with  its  fellow  to  form  the  basilar  artery. 
Prior  to  their  union  the}'  give  off  certain  small  branches 
distributed  to  the  spinal  cord  and  its  membranes,  as  well 
as  the  posterior  meningeal  artery  to  the  falx  cerebelli  and 
cerebellar  fossae. 

The  inferior  cerebellar  arteries  are  derived  from  the 
vertebrals  near  the  point  of  their  union,  or  from  the 
basilar  artery ;  they  wind  around  the  upper  part  of  the 
medulla  oblongata,  and  are  distributed  to  the  under  sur- 
face of  the  cerebellum,  their  branches  penetrating  th< 
fissure  between  its  hemispheres. 

The  BASILAR  ARTERY  is  the  vessel  resulting  from  the 
union  of  the  two  vertebrals ;  it  reaches  from  the  posterioi 
to  the  anterior  border  of  the  pons  Varolii,  and  terminates 
by  dividing  into  two  branches  for  the  cerebrum  ;  it  gives 
off  numerous  small  transverse  branches,  the  most  anterior 
of  which  are  called  the  superior  cerebellar  arteries  ;  these 
wind  around  the  cms  cerebri  on  each  side,  and  are  dis- 
tributed to  the  upper  surface  of  the  cerebellum,  anastomos- 
ing with  the  inferior  cerebellar  arteries. 

The  posterior  cerebral  arteries  are  the  terminal  branches 
of  the  basilar;  they  are  of  large  size,  and  are  directec 


MEMBRANES    AND     VESSELS.  81 

backward  around  the  crura  cerebri  to  the  posterior  lobes 
of  the  cerebrum,  which  they  supply.  The  arteries  are 
joined  near  their  commencement  by  the  posterior  com- 
mit ni  eating  arteries  from  the  internal  carotid. 

The  internal  carotid  artery  (p.  52)  supplies  the  anterior 
and  middle  cerebral  lobes,  and  at  the  base  of  the  brain  lies 
just  behind  the  optic  nerves. 

The  anterior  cerebral  arteries  are  given  off  from  the 
internal  carotids ;  they  penetrate  the  fissure  between  the 
cerebral  hemispheres  and  supply  the  inner  surfaces  of  the 
anterior  lobes  ;  as  the  two  arteries  are  about  to  enter 
this  fissure,  they  are  united  by  a  short  transverse  branch 
called  the  anterior  communicating  artery. 

The  middle  cerebral  arteries,  larger  than  the  preceding, 
pass  outward  from  the  internal  carotid  to  enter  the  fissure 
of  Sylvius  and  supply  the  anterior  and  middle  cerebral 
lobes.  Close  to  their  origin,  these  arteries  give  off  the 
posterior  communicating  branch  which  unites  them  with 
the  posterior  cerebral  arteries  of  the  basilar,  thus  com- 
pleting the  anastomoses  of  the  cerebral  arteries,  to  which 
the  term  circle  of  Willis  has  been  applied. 

The  arachnoid  and  pia  mater,  together  with  the  vessels,  may  now 
be  removed  by  carefully  tearing  them  away  with  the  forceps  ;  it  must 
be  done  in  such  a  manner  as  to  respect  the  origins  of  the  nerves,  many 
of  which  are  small,  and  so  easily  confounded  with  the  membranes,  that 
they  may  be  torn  away  unawares. 

The  removal  of  the  membranes  gives  an  opportunity 
to  define  better  than  has  yet  been  done,  the  different  parts 
of  the  encephalon,  their  limits,  and  the  subdivisions  into 
which  they  are  separated. 

The  ENCEPHALON  consists  of  the  medulla  oblongata,  pons 
Yarolii,  cerebellum,  and  cerebrum.  The  medulla  oblongata 
is  the  upper  part  of  the  spinal  cord.  The  pons  Yarolii  is 
a  broad  band  of  transverse  fibres  stretching  across  the 
upper  part  of  the  medulla  oblongata.  The  cerebellum,  or 
little  brain,  lies  beneath  the  posterior  part  of  the  cerebrum, 
and  is  composed  of  two  lateral  halves  or  hemispheres. 
The  cerebrum,  or  large  brain,  constituting  the  principal 
part  of  the  encephalon,  is  composed  likewise  of  two  hemi- 
spheres, but  is  also  divided  into  anterior,  middle,  and  pos- 
terior lobes  ;  the  anterior  and  middle  lobes  are  separated 
by  a  sulcus  called  the  fissure  of  Sylvius;  the  limit  between 
the  middle  and  posterior  lobes  is  indicated  by  a  line  cor- 


82      ANATOMY  OF  THE  HEAD  AND  NECK. 

responding  to  the  anterior  border  of  the  cerebellum.  Th< 
convexity  of  the  cerebrum  shows  no  marks  of  the  subdiv 
sion  into  lobes. 

ORIGINS    OF    THE    CRANIAL    NERVES. 

The  CRANIAL  NERVES,  with  the  exception  of  the  spin? 
accessory,  have  their  origin   in  the  encephalon  and  p 
through  apertures  in  the  skull.     The  origin  of  a  nerve  i* 
described  as  either  apparent  or  deep,  the  former  term  r< 
ferring  to  the  point  at  which  it  appears  superficially,  an< 
the  latter  to  its  commencement  in  the  nervous  substan< 
The  apparent  origin  of  the  nerves  will  alone  be  given. 

The  FIRST,  or  OLFACTORY  NERVE,  lies  in  a  sulcus  on  th< 
under  surface  of  the  anterior  lobe  of  the  cerebrum  ;  it  i; 
prismatic  in  form,  and  terminates   anteriorly  in  a  bull 
posteriorly  it  is  connected  with  the  cerebrum    by  thn 
roots :  an  inner  root,  not  always  apparent,  from  the  mm 
part  of  the  anterior  lobe,  a  middle  root  from  the  posterioi 
part  of  the  sulcus  in  which  the  nerve  lies,  and  an  exterm 
root  from  the  posterior  lip  of  the  fissure  of  Sylvius. 

To  see  the  middle  root,  the  nerve  must  be  reflected  and  examim 
from  its  deep  surface. 

-  The  SECOND,  or  OPTIC  NERVE,  is  the  largest  of  the  crani 
nerves.     Anteriorly  the  nerves  of  the  two  sides  unite  an 
form  the  optic  commissure,  or  chiasma ;  behind  the  co 
fnissure  the  nerve  is  called  the  optic  tract ;  it  winds  aroun 
the  crus  cerebri,  and  splits  into  two  parts,  which  may 
traced  back  to  the  optic  thalamus  and  the  corpora  quad 
gemina. 

The  THIRD,  or  MOTOR  OCULI  NERVE,  arises  just  in  front 
of  the  pons  Yarolii,  near  the  locus  perforatus,  from  th 
inner  side  of  the  crus  cerebri. 

The  FOURTH,  or  TROCHLEARIS  NERVE,  the  smallest  of  th 
cranial  nerves,  emerges  between  the  cerebrum  and  cerebe 
him  at  the  outer  side  of  the  crus  cerebri,  round  which 
winds.     It  may  be  traced  to  the  valve  of  Yieussens. 

The  FIFTH,  or  TRIFACIAL  NERVE,  springs  from  the  side 
of  the  pons  Varolii  near  its  anterior  border,  where  it 
emerges  as  two  roots,  separated  from  each  other  by  a  slight 
interval. 

The  SIXTH,  or  ABDUCENS  NERVE,  springs  from  the  upper 
part  of  the  corpus  pyramidal e  of  the  medulla  oblongata, 
close  behind  the  posterior  border  of  the  pons  Yarolii. 


it 

« 


MEDULLA    OBLONOATA    AND    PONS    VAROLII.      83 

The  SEVENTH  NERVE  consists  of  two  trunks,  the  FACIAL 
and  the  AUDITORY.  The  facial  is  the  smaller  of  the  two  and 
most  internal.  It  arises  from  the  medulla  oblongata,  be- 
tween the  olivary  and  restiform  bodies,  close  to  the  pons 
Varolii.  The  auditory  trunk  arises  by  distinct  filaments 
from  the  floor  of  the  fourth  ventricle.  A  small  bundle  of 
nervous  filaments  lies  between  these  two  nerves,  and  is 
called  the  intermediate  portion  of  Wrisberg ;  it  unites  with 
the  facial  nerve. 

The  EIGHTH  NERVE  consists  of  three  trunks,  the  GLOSSO- 
PHARYNGEAL,  the  PNEUMOGASTRic,  and  the  SPINAL  ACCES- 
SORY ;  they  are  all  situated  along  the  side  of  the  medulla 
oblongata. 

The  glosso-pharyngeal  nerve  is  the  smallest  of  the  three, 
and  arises  by  three  or  more  filaments,  springing  from  the 
restiform  body,  close  to  the  facial  nerve. 

The  pneumogastric,  or  par  vagum  nerve,  arises  bel<fw 
the  preceding,  also  from  the  restiform  body,  by  a  series 
of  filaments  which  are  finally  gathered  into  a  flat  band. 

The  spinal  accessory  nerve  consists  of  two  parts,  one 
being  accessory  to  the  pneumogastric  and  the  other  spinal. 
The  accessory  part  arises  from  the  spinal  cord  by  a  series 
of  minute  filaments  in  a  line  with  the  pneumogastric,  ex- 
tending as  low  as  the  first  cervical  nerve;  this  portion  does 
not  unite  with  the  pneumogastric  nerve  until  it  gets  outside 
the  skull.  The  spinal  part  is  a  round  cord  arising  by  fila- 
ments from  the  spinal  cord,  as  low  down  as  the  sixth 
cervical  nerve.  The  glosso-pharyngeal,  pneumogastric,  and 
spinal  accessory  nerves  converge  and  meet  just  below  the 
crus  cerebelli. 

The  NINTH,  or  HYPOGLOSSAL  NERVE,  arises  by  a  series 
of  filaments  from  the  sulcus,  between  the  pyramidal  and 
olivary  bodies  of  the  medulla  oblongata,  in  a  line  with  the 
anterior  roots  of  the  spinal  nerves. 

MEDULLA  OBLONGATA  AND  PONS  ^AROLII. 

The  MEDULLA^BLONGATA  is  the  upper  enlarged  portion 
of  the  spinal  cord.  Its  shape  is  pyramidal  and  its  length 
is  about  an  inch  and  a  quarter ;  its  base  is  limited  by  the 
transverse  fibres  of  the  pons  Yarolii,  but  its  apex  blends 
with  the  cord  and  is  not  as  definitely  marked.  The  anterior 
surface  is  convex,  the  posterior  is  somewhat  concave  an'd 
forms  the  floor  of  the  fourth  ventricle.  It  is  divided  into 
halves  by  a  median  longitudinal  fissure  in  front  and  behind, 


84  ANATOMY    OF    THE     HEAD    AND     NECK. 

the  anterior  ceasing  at  the  pous  Yarolii  in  a  dilated  pa 
called  the  foramen  caecum;  the  posterior  is  prolonged  in 
the  floor  of  the  fourth  ventricle.    Each  half  of  the  medulla 
made  up  from  the  three  lateral  divisions  of  the  spinal  co 
indications  of  which  still  exist,  though  they  are  somewh 
differently  arranged  and  changed  in  form.     That  porti 
nearest  the  longitudinal  fissure  in  front,  is  called  the  an 
rior  pyramid  or  corpus  pyramidale ;  at  about  an  inch  belo 
the  pons  Varolii  the  pyramids  of  the  two  sides  communica 
across  the  anterior  longitudinal  fissure  by  what  is  called 
decussation  of  their  fibres.     The  anterior  pyramids  are  t 
continuation  upward  of  the  anterior  columns  of  the  spin 
cord.    Next  the  anterior  pyramids  comes  the  corpus  oliva 
This  is  an  oval  projection,  separated  by  a  groove  on  ea 
side  from  the  anterior  pyramids  in  front,  and  the  restifor 
body  behind ;  its  upper  end  is  the  most  prominent,  and  d 
n^t  quite  reach  the  pons  Yarolii ;  its  lower  end  is  characte 
ized  by  some  transverse  fibres  arching  over  its  surface,  whi 
are  called  arciform  fibres.    That  part  of  the  medulla  belo 
the  olivary  body  is  continuous  with  the  lateral  column 
the  spinal  cord,  and  is  here  sometimes  called  the  later 
tract ;  its  fibres  are  continued  upward,  much  diminished 
size,  between  the  olivary  and  restiform  bodies.     On  eac 
side  of  the  posterior  longitudinal  fissure  is  the  corpus  resti- 
forme.     This  is  the  largest  prominence  of  the  medulla,  and 
by  its  lateral  projection  gives  width  to  its  upper  part.     The 
posterior  pyramids  are  placed  on  each  side  of  the  posteri 
longitudinal  fissure,  lower  down  than  the  restiform  bodi 
and  are  the  continuation  upward  of  the  posterior  colum 
of  the  spinal  cord;  at  the  lower  part  of  the  medulla  th 
diverge  and  become  blended  with  the  restiform  bodies. 

The  PONS  YAROLII,  or,  as  it  is  sometimes  called,  t 
TUBER  ANNULARE,  is  situated  above  the  medulla  oblonga 
and  between  the  hemispheres  of  the  cerebellum ;  it  is  of 
square  shape,  the  anterior  border  arching  over  the  crura 
cerebri,  and  the«posterior  over  the  medulla  oblongata.    Th 
superficial  fibres  of  the  pons  Yarolii  aflt  transverse,  an 
collect  together  on  each  side  to  form  the  crura  cerebell 
the  deep  fibres  are  longitudinal,  and  are  prolonged  upw 
from  the  medulla.     The  crura  cerebri  are  large  stalk-like 
bodies  emerging  from  the  anterior  border  of  the  pons  Yarolii 
and  dipping  into  each  lateral  hemisphere  of  the  cerebrum; 
as  they  enter  the  hemispheres  they  are  crossed  transversely 
by  the  optic  tract. 


ura 
rhe 
find 

s 


BASE     OF    THE    CEREBRUM.  85 


BASE   OF   THE  CEREBRUM. 

Between  the  crura  cerebri  on  each  side  and  the  optic 
commissure  in  front  is  the  inter-peduncular  space,  con- 
taining the  locus  perforatus,  the  corpora  albicantia,  and 
the  tuber  cinereum. 

I  The  locus  perforatus,  sometimes  called  the  pons  Tarini, 
r  posterior  perforated  space,  is  a  layer  of  whitish-gray 
substance,  between  the  corpora  albicantia  in  front,  and  the 
pons  Y arolii  behind.  It  gets  its  name  from  being  perforated 
by  numerous  arterial  twigs,  intended  for  the  interior  of  the 
brain. 

The  corpora  albicantia  are  two  small  round  bodies,  placed 
just  behind  the  optic  commissure;  they  are  the  termination 
of  the  crura  of  the  fornix. 

The  tuber  cinereum  is  a  mass  of  gray'matter  between  the 
corpora  albicantia  and  the  optic  commissure;  it  forms  the 
floor  of  the  third  ventricle;  projecting  from  it  is  a  small 
conical  body  called  the  infundibulum,  which  is  connected 
with  the  pituitary  body. 

The  pituitary  body  lies  in  the  sella  turcica,  and  has  been 
examined  in  connection  with  the  base  of  the  skull  (p.  29). 

If  the  two  hemispheres  of  the  brain  be  gently  parted  an- 
teriorly, the  corpus  callosum  will  be  seen;  this  is  the  broad 
transverse  band  which  unites  the  two  hemispheres  of  the 
brain;  it  has  a  rounded  border  in  front,  called  its  genu, 
from  which  it  extends  backward  under  the  name  of  the 
rostrum,  forming  a  thin,  concave  margin,  to  which  is  joined 
a  layer  of  gray  substance,  called  ^lamina  cinerea,  which 
unites  it  posteriorly  with  the  tuber  cinereum.  Laterally 
the  corpus  callosum  will  be  seen  extending  into  the  ante- 
rior lobes  of  the  lateral  hemispheres.  A  band  of  white 
substance,  diverging  on  either  side,  crosses  the  substantia 
pertbrata  to  lose  itself  at  the  entrance  of  the  fissure  of 
Sylvius.  The  divergent  processes  are  known  as  the  pedun- 
cles of  the  corpus  callosum.  The  corpus  callosum  will  be 
further  examined  in  connection  with  the  interior  of  the 
brain. 

The  fissure  of  Sylvius  is  the  separation  between  the  an- 
terior and  middle  lobes ;  externally  the  fissure  divides  into 
two  parts,  one  of  which  passes  before  and  the  other  behind 
a  cluster  of  convolutions  called  the  island  of  Reil.  At  the 
inner  extremity  of  the  fissure  is  a  triangular  spot,  called 
8 


8G  ANATOMY    OF    THE     HEAD    AND     NECK. 

the  substantia  perforata,  or  anterior  perforated  space,  froi 
being  pierced  by  a  number  of  openings  for  small  arteries 
its  inner  side  is  continuous  with  the  lamina  cinerea. 

UPPEE  SURFACE  AND  INTERIOR  OF  THE  CEREBRUM. 

The  brain  is  to  be  turned  over  to  bring  its  convexity  uppermost ; 
roll  of  cloth  should  support  the  whole,  and  elevate  the  anterior  lol 
so  as  to  bring  them  on  a  level  with  the  posterior. 

The  two  hemispheres  are  separated  by  a  median  lonj 
tudinal  fissure,  at  the  bottom  of  which  will  be  seen  tl 
broad  white  band  of  the  corpus  callosum.  interrupting  the 
fissure  at  its  central  part,  but  leaving  the  separation  ol 
the  hemispheres  complete  both  in  front  and  behind  it.  The 
superficies  of  the  hemispheres  is  marked  by  tortuous  emi- 
nences called  gyri,  or  convolutions,  and  by  intervening  d( 
pressions  called  sulci.  Some  of  these  convolutions  have 
been  named,  as,  for  instance,  that  at  the  bottom  of  the 
median  fissure,  where  the  hemisphere  rests  upon  the  corpus 
callosum,  which  is  called  the  convolution  of  the  corpus  cal- 
losum or  gyrus  fornicalus.  The  hemispheres  of  the  cere- 
brum sometimes  present  a  want  of  symmet^.as  to  size; 
Bichat  believed  this  to  be  a  condition  inconsistent  with  a 
perfect  performance  of  the  functions  of  the  brain:  no  more 
striking  proof  of  the  incorrectness  of  such  a  view  can  be 
found  than  the  fact  that  the  brain  of  Bichat  himself  pre- 
sented this  very  peculiarity. 

The  upper  part  of  each  hemisphere  is  to  be  removed  by  a  horizontal 
section  carried  as  low  down  as  the  convolution  of  the  corpus  callosum. 

The  section  thus  made  will  show  that  each  convolution 
consists,  superficially,  of  a  layer  of  grayish-colored  cere- 
bral substance,  lying  upon  a  whiter  structure  constituting 
the  central  portion  of  the  section;  the  gray  matter  is  called 
cortical,  and  the  white  medullary.  If  the  convexity  of  a 
single  hemisphere  has  been  cut  away,  the  medullary  matter 
of  that  side  will  be  seen  to  have  an  oval  shape;  this  is  called 
the  centrum  ovale  minus;  if  both  have  been  cut  awa}^,  a 
larger  medullary  surface  is  exposed,  and  the  two  ovals  will 
be  found  to  constitute  one  large  oval,  to  which  the  name  cen- 
trum ovale  majus  is  given;  the  surface  of  this  section,  in  a 
recent  brain,  is  dotted  with  minute  bloody  points  resulting 
from  the  division  of  small  vessels. 

The  CORPUS  CALLOSUM  is  the  great  commissure  of  the 
brain.  It  is  about  three  inches  in  length;  its  fibres  are 


SURFACE    AND    INTERIOR    OF    CEREBRUM.        87 

transverse  and  marked  along  the  central  line  by  a  raphe  ; 
if  the  convolution  called  g3rrus  fornicatns  be  cut  through 
transversely,  and  turned  one  part  forward  and  the  other 
backward,  a  white,  longitudinal  band  of  fibres,  lying  upon 
the  corpus  callosura,  will  be  exposed,  called  the  stride  lon- 
gitudinales  laterales,  or  covered  band  of  Reil.  In  front, 
the  corpus  callosura  bends  round  to  the  base  of  the  brain, 
the  bend  being  called  its  genu ;  posteriorly  it  forms  a  thick 
rounded  border ;  on  each  side  it  forms  the  roof  of  the 
cavities  in  the  hemispheres  called  the  lateral  ventricles, 
and,  by  its  under  surface,  is  connected  with  the  septum 
lucidum  anteriorly  and  with  the  fornix  posteriorly. 

The  ventricles  of  the  brain  are  cavities  which  exist  in  its 
interior ;  they  are  five  in  number.  One  is  found  in  the  cen- 
tral part  of  each  hemisphere;  these  are  called  lateral  ven- 
tricles, and  constitute  the  first  and  second ;  the  third 
occupies  the  middle  line  of  the  brain  near  its  under  surface; 
the  fourth  is  between  the  cerebellum  and  the  posterior 
surface  of  the  medulla  oblongata  and  pons  Yarolii;  the 
fifth  is  in  the  partition  which  separates  the  two  lateral 
ventricles  from  each  other. 

The  lateral  ventricle  of  either  side  is  displayed  by  shaving  off  as 
much  of  the  corpus  callosum  and  central  medullary  substance  of  each 
hemisphere  as  constitutes  its  roof;  the  escape  of  a  fluid  which  is 
ordinarily  present,  warns  the  dissector  of  his  arrival  in  the  cavity  of 
the  ventricle. 

The  LATERAL  VENTRICLE  is  a  narrow  interval  extending 
into  the  anterior,  middle,  and  posterior  lobes  of  the  hemis- 
phere by  three  prolongations  called  cornua;  the  anterior 
cornu  is  directed  outward ;  the  posterior,  which  is  small, 
turns  inward,  and  the  descending,  middle,  or  inferior  cornu 
penetrates  in  a  spiral  manner  into  the  middle  lobe.  This 
ventricle  presents  from  before  backward  the  following  parts 
for  examination,  viz : — 

Corpus  striatum,  Hippocampus  major, 

Taenia  semicircularis,  Hippocampus  minor, 

Optic  thalamus,  Septum  lucidum, 

Choroid  plexus,  Fornix. 

The  corpus  striatum,  a  large  oval  body  in  the  anterior 
part  of  the  lateral  ventricle,  is  so  called  from  the  striated 
lines  of  white  and  gray  matter  which  are  seen  upon  cutting 
into  its  substance.  The  broad  end,  directed  forward,  is 


88 


ANATOMY  OF  THE  HEAD  AND  NECK. 


separated  by  the  septum  lucidum  from  its  fellow  of  tl 
opposite  side;  its  narrow  end  projects  backward  outsi( 
the  optic  thalamus. 

The  tsenia  semicircular  is  is  a   narrow  band   of  1( 
tudinal  fibres,  lying  between  the  corpus  striatum  and  the 
optic  thalamus;  in  front  it  joins  the  pillar  of  the  fornb 
and  posteriorly  is  lost   in  the  descending  cornu  of  the 
ventricle. 

The  optic  thalamus  is  an  oblong  body,  a  part  of  the  uppei 
surface  of  which  is  alone  seen,  the  rest  being  covered 
the  fornix ;  its  posterior  portion  projects  into  the  descent 
ing  cornu  of  the  ventricle;  its  other  relations  will  be  sul 
sequently  examined. 

The  choroid  plexus  is  a  vascular  fringe,  formed  from  the 
pia  mater,  which  extends  obliquely  across  the  ventricle 
posteriorly  it  penetrates  into  the  descending  cornn,  am 
anteriorly  it  communicates  with  the  plexus  of  the  othei 
side  through  the  space  behind  the  crura  of  the  fornix 
they  arch  downward,  called  theforamenofMonro,  and  this 
may  be  demonstrated  by  pulling  the  plexus  gently  with 
pair  of  forceps,  while  the  septum  lucidum  is  held  aside  b 
the  handle  of  a  scalpel. 

The  hippocampus  major  is  the  projection  which  lies  at 
the  commencement  of  the  descending  cornu,  behind  the 
choroid  plexus ;  it  follows  the  direction  of  the  cornu,  an< 
its  extremity  has  been  likened  to  the  foot  of  an  animal,  the 
two  or  three  indentations,  with  corresponding  elevations, 
which  are  found  upon  it  having  been  named  pes  hippocampi. 
In  order  to  see  this,  the  cornu  must  be  laid  open  by  a  can 
ful  division  of  the  external  wall  of  the  hemisphere,  follow- 
ing a  direction  backward,  outward,  and  downward,  an< 
then  forward   and   inw^ard.      The   primary  letters  of  th( 
words  used  to  express  the  curve  taken  by  the  cornu  hav( 
given  rise  to  a  mnemonic  symbol,  BODFI,  by  which  the  sti 
dent  may  with  ease  remember  its  course. 

The  hippocampus  minor  is  the  projection  which  occupies 
nearly  all  the  space  of  the  posterior  cornu.  Between  th< 
two  hippocampi  is  an  elevation  called  the  eminentia  colic 
teralis. 

The  corpus  callosum  is  to  be  out  through  transversely  at  its  middle  : 
the  anterior  half  is  to  be  raised  by  separating  it  from  the  fornix  am 
reflected  forward ;  this  exposes  the  septum  lucidum  and  its  ventricle. 
The  posterior  half  is  to  be  raised  and  reflected  backward  ;  the  forni: 
will  thus  be  exposed. 


SURFACE  AND  INTERIOR  OF  CEREBRUM.    89 

The  septum  lucidum  is  a  thin,  triangular,  and  almost 
transparent  partition  between  the  lateral  ventricles  ;  it  con- 
sists of  two  layers,  inclosing  a  space  which  is  the  fifth  ven- 
tricle. The  septum  lucidum  is  so  delicate  a  structure,  that 
if  the  decomposition  of  the  brain  has  at  all  advanced,  it 
will  only  be  seen  as  it  tears  away  during  the  gentle  lifting 
of  the  anterior  portion  of  the  corpus  callosum,  to  the  under 
surface  of  which  it  is  attached  superiorly;  its  lower  border 
corresponds  to  the  rostrum,  and  its  apex  to  the  genu  of  the 
corpus  callosum ;  its  base  is  applied  to  the  fornix  as  it 
arches  downward  in  front. 

The  fornix  is  a  thin,  horizontal  la}7er  of  white  substance, 
triangular  in  outline,  attached  along  the  median  line  to  the 
under  surface  of  the  corpus  callosum,  behind  the  septum 
lucidum ;  in  front  it  arches  over  the  foramen  of  Monro,  to 
form  on  either  side  crura,  which  terminate  in  the  corpora 
albicantia  and  optic  thalami ;  posteriorly  it  is  continuous 
with  the  corpus  callosum,  and  it  sends  off  on  each  side  an 
expansion  called  its  posterior  pillars,  which  lie  along  the 
hippocampus  major.  It  is  this  part  of  the  fornix  which  is 
seen  in  the  floor  of  the  lateral  ventricle  when  first  laid  open, 
and  the  thin  edge  of  which,  concealed  by  the  choroid  plexus, 
is  called  the  corpus  fimbrialum  or  tsenia  hippocampi.  If  the 
fornix  be  divided  anteriorly  and  reflected  backward,  there 
will  be  seen  upon  its  under  surface,  between  its  diverging 
pillars  behind  and  its  crura  in  front,  a  triangular  space 
marked  by  transverse  lines,  and  called  .the  lyra.  The  re- 
flection of  the  fornix  exposes  the  optic  thalami.  and  it  will 
be  seen  that  it  rests  upon  and  covers- in  these  bodies  in 
nearly  their  whole  extent.  If  we  follow  the  fornix  by  its 
free  edge  or  t?enia  hippocampi  into  the  descending  cornu  of 
the  ventricle,  we  shall  find,  on  lifting  it  from  the  optic  tha- 
lamus,  that  there  is  a  fissure  extending  downward  to  the  ex- 
tremity of  the  posterior  cornu,  and  forward  to  the  foramen 
of  Monro,  through  which  an  expansion  of  the  pia  mater 
enters  the  ventricle,  and  forms  the  fringed  margin  which 
lies  along  the  tsenia  hippocampi,  called  the  choroid  plexus. 
This  is  called  the  transverse  fissure  of  the  cerebrum,  or  the 
fixture  of  Bichat.  The  ventricle  is  made  a  closed  cavity 
by  the  union  of  its  lining  membrane  with  that  portion  of 
the  pia  mater  which  passes  through  this  fissure. 

The  central  part  of  the  pia  mater  which  thus  enters  the 
ventricles,  lying  beneath  the  fornix,  and  corresponding  to 
it  in  shape  and^extent,  is  called  the  velum  interpositum ;  its 

8* 


90  ANATOMY     OF     THE     HEAD     AND     NECK. 

upper  surface  is  in  contact  with  the  fornix,  and  its  margii 
late  ."illy  is  the  choroid  plexus  ;  its  under  surface  is  the  roc 
of  the  third  ventricle,  and  it  covers  the  pineal  body  and 
part  of  each  optic  thalamus.  The  velum  is  traversed  aloiij 
its  median  line  by  two  veins  called  venae  Galeni,  whicl 
commencing  at  the  foramen  of  Monro,  terminate  posteriori; 
at  the  straight  sinus. 

The  velum  interpositum  is  now  to  be  raised  and  thrown  backwai 
It  must  be  done  with  care  not  to  injure  the  parts  beneath. 

On  the  under  surface  of  the  velum  are  the  choroid  plexust 
of  the  third  ventricle  ;  continuous  in  front  by  the  foramei 
of  Monro  with  the  plexus  choroides  of  the  lateral  ventricle 
which  they  resemble  in  their  structure,  they  are  conned 
posteriorly  with  the  pineal  gland,  and  this  connection  is 
be  remembered  in  removing  the  velum,  or  that  body  m 
be  torn  away  with  it. 

The  THIRD  VENTRICLE  is  an  interval  between  the  optic 
thalami;  its  roof  is  the  velum  interpositum,  and  its  flo< 
the  tuber  cinereum  at  the  base  of  the  brain  ;  in  its  anteri< 
portion  are  the  descending  crura  of  the  fornix  and  the  an- 
terior commissure ;  in  its  posterior  portion  the  pineal  gland 
and  posterior  commissure,  covering  in  the  corpora  quadrigc 
mina.     On  its  two  sides  we  have  the  optic  thalami,  an< 
crossing  from  one  to  the  other  of  these,  the  middle  or  soi 
commissure. 

The  anterior  commissure  is  a  round  bundle  of  white 
fibres,  situated  just  in  front  of  the  crura  of  the  fornix, 
which  must  be  separated  in  order  to  display  it;  it  crosses 
between  the  corpora  striata. 

The  middle  or  soft  commissure,  frequently  torn  across  in 
examining  the  brain,  consists  of  gray  matter,  and  connects 
the  adjacent  sides  of  the  optic  thalami. 

The  posterior  commissure  is  a  flattened  white  band,  con- 
necting the  optic  thalami  posteriori}^. 

The  space  between  the  anterior  and  middle  commissures 
is  called  the  foramen  commune  anterius,  or  foramen  of 
Monro,  and  is  the  medium  of  communication  between  the 
lateral  and  third  ventricles,  .and  of  the  transmission  of  the 
choroid  plexuses  and  their  termination,  the  venae  Galeni. 
This  foramen  is  also  called  the  Her  ad  infundibulum,  from 
leading  down  to  the  funnel-shaped  cavity  of  the  infundibu- 
lum.  (p.  29.) 

The  space  between  the  middle  and  posterior  commissures 


YV    I 

5 


SURFACE     AND    INTERIOR    OF    CEREBRUM.        91 

is  called  the  foramen  commune  posterius ;  it  is  the  point 
from  which  a  canal,  called  the  aqueduct  of  Sylvius,  or  Her  a 
tcrtio  ad  quartum  ventriculum,  leads  backward  through  the 
base  of  the  corpora  quadrigemina  to  the  fourth  ventricle, 

mpleting  the  intercommunication  existing  between  all 
he  ventricles.  The  two  lateral  ventricles  communicate 
with  each  other  transversely,  and  with  the  third  perpen- 
icularly,  through  the  foramen  of  Munro,  and  we  have  just 

en  how  the  third  and  fourth  ventricles  are  connected.  It 
.8  a  disputed  point  whether  the  fifth  ventricle  communicates 
with  the  third ;  if  it  does,  it  is  by  a  very  narrow  orifice  at 
the  angle  formed  by  the  inferior  and  posterior  borders  of 
the  septum  lucidum.  The  weight  of  authority  is  against 
the  existence  of  an}7  aperture  at  that  point. 

The  optic  thalamus  is  a  square-shaped  body  forming  part 
of  both  the  lateral  and  the  third  ventricles;  it  forms  a 
large  part  of  the  descending  cornu  of  the  former,  where  it 
presents  two  rounded  tubercles  called  corpus  geniculatum 
c.rtt'rnum  and  internum,  and  is  in  relation,  externally  with 
the  corpus  striatum  and  substance  of  the  hemispheres. 
Anteriorly  the  thalami  are  connected  with  the  crura  of  the 
fornix  as  they  descend  to  the  corpora  albicantia,  and  poste- 
riorly they  are  joined  by  bands  from  the  pineal  body  and 
the  corpora  quadrigemina. 

The  pineal  body  is  a  small  conical  mass  of  a  reddish 
color  and  vascular  character,  situated  above,  and  connected 
by  its  base  with,  the  posterior  commissure;  it  lies  between 
the  anterior  pairs  of  the  corpora  quadrigemina ;  it  is  also 
connected  with  the  optic  thalami  by  white  bands  called  its 
peduncles.  The  pineal  body  is  hollowed  out  into  a  cavity 
containing,  in  addition  to  a  viscid  fluid,  a  quantity  of 
gritty  matter  called  acervulus,  easily  detected  by  rubbing 
a  portion  of  the  mass  between  the  fingers.  The  pineal 
body  was  supposed  by  Descartes  to  be  the  seat  of  the  soul. 

The  corpora  quadrigemina  are  four  small,  rounded  pro- 
tuberances arranged  in  pairs  and  separated  by  grooves ; 
each  pair  is  situated  on  the  cms  cerebri  of  the  same  side. 
The  anterior  pair,  called  the  nates,  are  the  largest ;  they  are 
oblong  in  shape  and  send  forward  a  white  band  to  join  the 
optic  thalami.  The  posterior  pair,  called  the  testes,  are 
rounder  and  whiter  than  the  preceding,  and  are  also  con- 
nected with  the  thalami  by  a  white  band.  The  iter  a  terf/o 
ad  quartum  ventriculum  passes  longitudinally  through  the 
base  of  the  corpora  quadrigemina. 


92  ANATOMY     OP    THE     HEAD     AND     NECK. 

By  drawing  back  the  cerebellum  two  large  white  core 
will  be  seen  extending  from  the  corpora  quadrigemina  t( 
the  cerebellum  ;  these  are  termed  the  processus  e  cerebelh 
ad  testes,  or  superior  peduncles  of  the  cerebellum.  Betweei 
them  is  stretched  a  thin  layer  of  cerebral  substance,  covei 
ing  in  the  passage  from  the  third  to  the  fourth  ventricle, 
well  as  a  part  of  the  fourth  ventricle  itself;  this  is  the  vali 
of  Vieussens. 

CEREBELLUM. 

The  cerebellum  is  to  be  detached  from  the  remains  of  the  cerebrni 
by  carrying  the  knife  through  the  optic  thalami,  so  that  the  cert 
bellum,  with  the  corpora  quadrigemina,  pons  Varolii,  crura  cerebi 
and  medulla  oblongata,  shall  remain  united  together. 

The  CEREBELLUM,  or  little  brain,  lies  beneath  the  posl 
rior  lobes  of  the  cerebrum,  from  which,  in  the  cranial  cavit; 
it  is  separated  by  the  ten  tori  urn;  its  diameter  is  greatest 
from  side  to  side,  and  it  is  incompletely  divided  into  twc 
lateral  hemispheres.  Its  surface  is  marked  by  plates  01 
laminae  instead  of  convolutions,  and  between  these  ai 
fissures  lined  by  pia  mater ;  the  deeper  of  these  fissui 
break  the  hemispheres  into  imperfectly  marked  lobes. 

The  two  hemispheres  are  united  on  the  upper  or  cerebrt 
aspect  by  a  central,  constricted  isthmus,  called  the  superic 
vermiform  process;  in  front  of  this  is  a  notch  which  ei 
circles  the  corpora  quadrigemina  posteriorly,  called  im 
sura  cerebelli  anterior;  behind  the  isthmus  is  anothi 
notch  called  incisura  cerebelli  posterior.  Upon  the  und( 
surface  of  the  cerebellum  the  depression  which  receivi 
the  medulla  oblongata  is  called  the  vallecula,  and  at  the 
bottom  of  this  is  an  isthmus,  corresponding  to  that  coi 
necting  the  hemispheres  on  the  superior  surface,  and  calle< 
the  inferior  vermiform  process. 

The  cerebellum  is  united  to  the  rest  of  the  encephalon 
by  a  large  stalk-like  process  on  each  side.  This  process 
subdivides  into  three  rounded  cords,  called  peduncles.  The 
superior  peduncle,  or  processus  e  cerebello  ad  testes,  is 
directed  forward  to  the  corpora  quadrigemina,  and  forms 
the  anterior  part  of  the  lateral  boundary  of  the  fourth 
ventricle;  between  these  peduncles  is  the  valve  of  Vieussens. 
The  middle  peduncle,  or  processus  ad  poritem,  is  commonly 
called  the  cms  cerebelli,  and  is  the  largest  of  the  three 
peduncles.  Its  fibres  begin  in  the  lateral  part  of  the  cere- 
bellum, and  are  directed  forward  to  the  pons  Yarolii,  of 


fllH 

:;; 

as 

«i 
1 


CEREBELLUM.  93 

which  they  form  the  transverse  fibres,  uniting  with  the 
fibres  of  the  cms  of  the  opposite  side.  The  inferior  pedun- 
cle, or  processus  ad  medullam,  passes  downward  to  the 
medulla  oblongata  and  forms  part  of  the  restiform  body ; 
it  is  also  the  inferior  portion  of  the  lateral  boundary  of  the 
fourth  ventricle. 

The  FOURTH  VENTRICLE  is  a  space  bet  ween  the  cerebellum 
nd  the  posterior  aspect  of  the  medulla  oblongata  and  pons 

roliij  it  has  the  shape  of  a  lozenge,  the  points  of  which 
directed  upward  and  downward,  the  upper  extending 
as  high  as  the  superior  border  of  the  pons  Yarolii,  and  the 
wer  to  a  level  with  the  inferior  part  of  the  olivary  body. 

e  lower  half  of  this  space  has  been  called  the  calamus 
riptorius,  from  a  fancied  resemblance  to  the  tip  of  a  writ- 
ing pen  ;  its  lateral  boundaries  are  formed  by  the  superior 
peduncles  of  the  cerebellum  above,  and  by  the  restiform 
bodies  below  ;  its  roof  is  formed  by  the  valve  of  Yieussens 
and  the  sicles  of  the  peduncles  with  which  it  is  connected, 
and  by  the  under  part  of  the  superior  vermiform  process ; 
its  floor  corresponds  to  the  posterior  surfaces  of  the  medulla 
and  pons  Yarolii.  Along  the  centre  of  its  floor  is  a  median 
groove,  ending  at  the  point  of  the  calamus,  and  on  each  side 
of  the  groove  a  fusiform  elevation  called  the  eminentia  teres. 
The  eminentia  teres  is  crossed  by  white  streaks,  varying 
in  their  arrangement  and  not  always  recognizable,  called 
linese  transversse.  The  fourth  ventricle  communicates  with 
the  third  ventricle  through  the  Her  a  tertio  ad  quartum 
rrnfriculum,  and  by  this  canal  the  lining  membrane  of  the 
other  ventricles  is  prolonged  into  the  fourth. 

The  arachnoid  and  pia  mater  stretch  across  between  the 
medulla  oblongata  and  cerebellum,  at  the  lower  part  of  the 
ventricle,  under  the  name  of  the  valve  of  the  arachnoid. 
On  the  inner  surface  of  these  membranes  is  a  vascular  fold, 
called  the  choroid  plexus  of  the  fourth  ventricle.  The  ven- 
tricles communicate  with  the  sub-arachnoid  space  of  the 
encephalon  and  spinal  cord,  through  an  aperture  in  this 
membrane  just  above  the  calamus  scriptorius. 

A  vertical  section  of  the  cerebellum  shows  that  the 
laminae  of  its  hemispheres  are  composed  of  an  external 
layer  of  gray  matter  and  an  internal  layer  of  white  medul- 
lary substance,  the  white  part  being  derived  from  a  large 
medullary  centre  in  the  interior  of  each  hemisphere,  which 
in  one  direction  gives  rise  to  the  peduncles  of  the  cerebel- 
lum, and  in  the  other,  diverging  like  the  branches  of  a  tree, 


94  ANATOMY    OF    THE    HEAD    AND    NECK. 

enters  by  small  offsets  into  each  lamina ;  the  appearam 
thus.presented  is  called  the  arbor  vitse  cerebelli. 

A  portion  of  the  medullary  centre  of  the  cerebellum  wil 
be  found  inclosed  by  a  waved  or  dentated  gray  line ;  this 
is  called  the  corpus  rhomboideum,  and  a  similar  appearance, 
bearing  the  same  name,  may  be  found  in  the  olivary  bod; 
of  the  medulla,  on  slicing  it  obliquely  in  its  long  diameter. 

By  dividing  transversely  one  of  the  crura  cerebri,  a  large 
mass  of  gray  matter,  called  the  locus  niger,  will  be  found 
in  the  centre  of  the  section. 


DISSECTION  XIV. 

THE  INTERNAL  AUDITORY  APPARATUS. 

Tn  order  to  dissect  the  ear,  a  recent  temporal  bone  should  be 
obtained  ;  the  soft  parts,  already  examined,  should  be  removed.  The 
squamous  portion  of  the  bone  is  to  be  got  rid  of  by  a  vertical  cut 
through  the  root  of  the  zygoma,  and  the  anterior  wall  of  the  osseous 
portion  of  the  auditory  canal  is  to  be  cut  away  with  bone  forceps  ; 
this  will  expose  the  tympanic  membrane.  It  is  extremely  difficult, 
however,  to  get  an  idea  of  the  parts  contained  within  the  temporal 
bone ;  it  is  only  upon  a  model,  or  one  of  the  French  preparations, 
that  it  can  be  done  effectually.  The  dissector  may  find  his  work 
facilitated  by  softening  a  recent  bone  in  acid,  but  with  every  aid  the 
examination  will  require  a  very  considerable  amount  of  skill  and 
knowledge. 

The  internal  portions  of  the  auditory  apparatus  are  all 
contained  within  the  temporal  bone,  which  also  forms  a 
part  of  the  external  auditory  canal.  The  tympanic  mem- 
brane is  placed  at  the  bottom  of  this  canal,  and  separates 
the  external  portion  of  the  ear  from  that  constituting  the 
sentient  structure. 

The  osseous  portion  of  the  auditory  canal  is  about  three- 
quarters  of  an  inch  in  length ;  it  is  furnished  with  a  rough 
lip,  called  theprocessus  auditorius,  into  which  the  fibro-carti- 
lage  of  the  external  ear  is  inserted  ;  its  lower  wall  describes 
a  curve,  the  convexity  of  which  is  directed  upward,  and 
the  summit  of  which  hides  the  lower  part  of  the  tympanic 
membrane  from  view,  in  examinations  with  the  speculum 
auris. 

The  membrana  tympani  is  a  thin,  oval,  and  semi-trans- 
parent membrane,  attached  b}^  its  circumference  to  a  groove 


MIDDLE    EAR.  95 

in  the  bone  at  the  inner  end  of  the  auditory  canal ;  its  sur- 
face is  convex  internally,  and  concave  externally;  it  is 
placed  at  an  angle  of  45°  with  the  floor  of  the  canal.  One 
of  the  little  bones  of  the  ear,  the  malleus,  is  attached  to 
the  upper  part  of  its  internal  surface,  which  is  also  crossed 
by  the  chorda  tympani  nerve.  In  the  foetus  this  membrane 
is  connected  with  a  separate,  osseous  ring,  the  tympanic 
bone,  which  subsequently  unites  with  the  rest  of  the  tem- 
poral bone. 

* 

»  MIDDLE  EAR. 

The  tympanum  is  behind  the  tympanic  membrane,  and  is  exposed 
by  removing  the  bone  which  forms  the  roof  of  the  cavity,  in  such  a 
way  as  to  preserve  as  perfectly  as  possible  the  membrane  and  the 
lain  of  little  bones  within  it. 

The  TYMPANUM,  or  MIDDLE  EAR,  has  the  form  of  a  round, 
flat  box,  placed  on  edge ;  the  following  points  are  to  be 
noticed  within  its  cavity.  Upon  the  surface,  opposite  the 
membrana  tympani,  a  central  projection,  called  the  promon- 
tory ;  above  and  below  this,  two  apertures  opening  into  the 
labyrinth ;  the  superior  one  is  called  the  fenestra  ovalis, 

d  the  lower  the  fenestra  rotunda;  the  fenestra  rotunda 

closed  by  a  thin  membrane,  called  the  secondary  mem- 
brana tympani.  The  anterior  boundary  of  the  tympanic 
cavity  is  formed  by  the  membrana  tympani  and  a  part  of 
the  surrounding  bone;  above  the  membrane  maybe  seen 
ihefissura  Glaseri,  occupied  by  the  long  process  of  one  of 
the  small  bones  of  the  ear,  the  malleus,  and  by  a  small  mus- 
cle, the  laxator  tympani ;  crossing  the  membrana  tympani 
at  its  upper  part  is  the  chorda  tympani  nerve.  This  nerve 
is  a  long  but  slender  branch  of  the  facial ;  it  arises  about  a 
quarter  of  an  inch  from  the  stylo-mastoid  foramen,  and 
passes  forward  to  the  tympanum,  entering  that  cavity  just 
below  the  pyramid  ;  it  then  crosses  the  handle  of  the  mal- 
leus and  the  membrana  tympani  to  a  small  foramen  on  the 
inner  side  of  the  Glaserian  fissure,  through  which  it  passes, 
and,  emerging,  unites  with  the  gustatory  nerve. 

It  is  to  be  noticed  that  the  circumference  of  the  tympanic 
cavity  presents  a  rough  surface,  separated  superiorly  from 
the  cranial  cavity,  and  inferiorly  from  the  jugular  fossa, 
merely  by  a  thin,  osseous  plate;  this  is  an  anatomical  fact 
of  importance  in  connection  with  fractures  of  the  petrous 
portion  of  the  temporal  bone,  which,  if  at  this  point,  would 
lead  to  serious  complications.  At  the  posterior  part  of  the 


96  ANATOMY    OF    THE    HEAD    AND    NECK. 

circumference  is  an  orifice  leading  to  the  mastoid  cells 
below  this  aperture  is  a  projection  called  the  pyramid,  froi 
which  a  small  spiculum  of  bone  extends  to  the  promontory 
the  apex  of  this  pyramid  is  open,  and  from  it  emerges  tl 
stapedius  muscle ;  arching  up  from  the  pyramid,  above  t] 
fenestra  ovalis,  is  a  ridge  of  bone  marking  the  aqueduct 
Fallopius.  At  the  anterior  part  of -the  circumference  ai 
the  apertures  of  two  canals,  the  upper  one  of  which  coi 
tains  the  tensor  tympani  muscle,  and  the  lower  one  tl 
Eustachian  tube.  Between  these  two  canals  is  a  thii 
osseous  lamina,  called  the  processus  cockle  ar  if  or  mis. 

The  Eustachian  tube  is  the  channel  through  which  tl 
tympanic  cavity  communicates  with  the  fauces ;  it  is  ai 
inch  and  a  half  in  length,  and  is  partly  osseous  and  parti; 
cartilaginous  in  structure;  its  course  in  the  temporal  boi 
is  along  the  angle  of  union  of  the  squamous  and  petrous 
portions,  external  to  the  aperture  which  contains  the  cai 
tid  artery.  Its  cartilaginous  portion  has  been  alrea< 
described  (p.  62). 

The  tympanum  contains  three  small  bones.  They  extern 
in  a  line  across  the  cavity,  and  are  named  malleus,  incuf- 
and  stapes. 

The  malleus,  so  called  from  its  supposed  resemblance 
a  hammer,  is  large  at  one  end  (head),  and  small  and  tape 
ing  at  the  other  (handle)  ;  it  has  two  processes,  a  long  ai 
a  short;  the  short  process   springs  from  the  root  of  tl 
handle,  and  the  long  from  a  point  just  above  it;  the  loi 
process  extends  into  the  fissura  Glaseri ;  the  handle  is 
tached  to  the  membrana  tympani ;  upon  the  side  of  the  he* 
of  the  malleus  is  an  articulating  surface  which  unites  it  wil 
the  next  bone,  the  incus. 

The  incus,  or  anvil-shaped  bone,  consists  of  a  body  an< 
two  processes  ;  the  body  is  concave,  to  receive  the  head  of 
the  malleus ;  the  two  processes,  long  and  short,  shoot  01 
from  the  side  of  the  body,  opposite  its  articulating  surfac 
The  long  process  terminates  in  a  rounded  extremity  callc 
the  orbicular  process,  sometimes  described  as  a  sepan 
bone,  under  the  name  of  os  orbiculare.     The  orbicular  pi 
cess  unites  the  incus  with  the  third  bone,  the  stapes. 

The  stapes,  resembling  in  its  shape  a  stirrup,  has  a  base 
and  two  sides  which  unite  to  form  a  head.  The  head  is 
marked  by  a  superficial  depression  which  articulates  wi1 
the  orbicular  process  of  the  incus  ;  the  base,  which  is  a  thii 
osseous  plate,  is  fixed  over  the  fenestra  ovalis. 


INTERNAL    EAR.  9t 

These  bones  are  maintained  in  their  position  by  minute 
ligaments,  which  unite  them  to  each  other  and  to  the  sur- 
rounding walls.  Three  muscles,  also,  are  in  connection 
with  the  chain  of  bones. 

The  tensor  tympani^  the  largest  of  the  three  muscles,  is 
contained  in  an  osseous  canal,  the  orifice  of  which  has 
already  been  spoken  of  as  lying  above  that  of  the  Eusta- 
chian  tube.  It  arises  from  the  walls  of  this  canal,  and 
terminating  in  a  tendon  which  turns  round  the  processus 
cochleariformis  as  a  pulley,  is  inserted  into  the  inner 
border  of  the  handle  of  the  malleus,  at  its  base. 

The  stapedius  muscle  arises  from  a  canal,  in  the  interior 
of  the  pyramid  ;  it  ends  in  a  small  tendon  which  is  inserted 
into  the  neck  of  the  stapes. 

The  laxator  tympani  arises  from  the  spinous  proceSvS  of 
e  sphenoid  bone,  and  is   continued  *by  a  long  tendon 
rough  the  fissura  vjlaseri,  to  be  inserted  into  the  neck  of 
the  malleus,  above  its  long  process. 

INTERNAL    EAR. 

The  INTERNAL  EAR,  or  LABYRINTH,  is  composed  of  an 
osseous  and  a  membranous  portion.  The  osseous  labyrinth 
consists  of  the  vestibule,  the  semicircular  canals,  and  the 
cochlea;  the  membranous  labyrinth,  of  two  sacs,  called 
the  utricle  and  the  saccule. 

The  vestibule  is  exposed  by  enlarging  the  fenestra  ovalis. 

The  VESTIBULE  is  an  oval-shaped  cavity,  situated  behind 
the  posterior  wall  of  the  tympanum  ;  within  it  are  numerous 
openings;  five  of  these  belong  to  the  three  semicircular 
canals,  and  a  larger  one,  in  front  of  the  others,  leads  to  the 
cochlea.  A  vertical  ridge,  called  the  crista,  traverses  the 
inner  wall ;  below  this  is  a  small  circular  depression,  the 
fovea  hemispherica,  perforated  by  minute  orifices  which 
transmit  nervous  filaments  ;  this  depression  corresponds  to 
the  bottom  of  the  meatus  auditorius  internus.  On  the  roof 
of  the  vestibule  is  another  oval  depression  called  the  fovea 
semi-elliptica.  Behind  the  crista,  and  near  the  common 
opening  of  two  of  the  semicircular  canals,  is  the  internal 
opening  of  the  aquseductus  vestibuli,  the  other  orifice  of 
which  is  on  the  posterior  surface  of  the  petrous  portion  of 
the  temporal  bone;  through  it  pass  a  small  artery  and  vein. 
9 


98  ANATOMY    OF    THE    HEAD    AND     NECK. 

The  semicircular  canals,  above  and  behind  the  vestibule,  may 
followed  out  from  their  orifices  in  the  vestibule  by  a  file  and  strong 
knife  ;  some  of  the  instruments  used  by  dentists  are  applicable  to  this 
and  other  parts  of  the  dissection  of  the  internal  ear. 

The  SEMICIRCULAR  CANALS,  three  in  number,  are  of  un- 
equal length,  though  each  forms  more  than  half  a  circle ; 
the}^  communicate  by  both  ends  with  the  vestibule ;  as  two 
of  them,  however,  blend  together,  they  have  but  five  open- 
ings into  that  cavity.  Each  canal  has  a  dilated  extremity, 
called  its  ampulla.  From  their  different  directions  the 
canals  have  been  named  superior,  oblique,  and  horizontal. 
The  superior  canal  crosses  the  upper  part  of  the  petrous 
bone  transversely,  on  the  anterior  surface  of  which,  within 
the  cranium,  it  makes  a  marked  projection ;  its  ampulla  is 
at  the  outer  end  of  the  canal ;  its  inner  end  joins  with  the 
oblique  canal.  The  oblique  canal  is  directed  backward 
toward  the  posterior  surface  of  the  temporal  bone ;  its 
inner  end  is  in  common  with  that  of  the  superior  canal, 
and  its  outer  end  is  furnished  with  an  ampulla.  The  hori- 
zontal canal  is  the  shortest  of  the  three,  and  has  separate 
orifices ;  it  lies  in  the  substance  of  the  bone,  nearly  on  a 
level  with  the  fenestra  ovalis ;  its  ampulla  is  on  the  outer 
side,  close  above  that  aperture. 

The  cochlea  is  anterior  to  the  vestibule.  To  expose  it,  the  surface 
of  bone  forming  the  promontory  of  the  tympanum  must  be  filed  or 
cut  away ;  the  surface  of  the  petrous  bone  above  it  should  also  be 
removed. 

The  COCHLEA  is  conical  in  form,  with  its  base  turned  to- 
ward the  meatus  auditorius  internus.    It  resembles  a  snail- 
shell  in  construction,  consisting  of  a  tube  wound  spiralb 
round  a  central  part  or  axis ;  the  tube  makes  two  turns 
and  a  half  round  the  axis,  and  terminates  in  a  closed  ex- 
tremity, called  the  cupola ;  the  axis,  or  modiolus,  is  th< 
bony  centre  included  within  the  coils  of  the  spiral  tube ;  its 
shape  is  conical,  and  its  size  diminishes  as  it  reaches  the 
apex  of  the  cochlea.     Winding  round  the  axis  is  a  thii 
osseous  plate,  called  the  lamina  spiralis,  which  is  project* 
into  the  spiral  tube,  and  forms  part  of  a  septum,  completec 
by  a  membrane,  which  divides  the  tube  into  two  passages  ; 
these,  however,  communicate  at  the  apex  of  the  cochlea  by  a 
foramen,  called  the  helicotrema.     The  lamina  spiralis  termi- 
nates at  the  apex  of  the  cochlea,  in  a  hook-shaped  process 
called  the  hamulus.     The  two  divisions  of  the  spiral  tul 


1 1 

; 


INTERNAL    EAR.  99 

are  called  scalse,  that  nearest  to  the  apex  being  the  scala 
vestibuli,  and  the  other  the  scala  tympani;  the  scala  vesti- 
bnli  opens  by  an  oval  aperture  into  the  anterior  part  of  the 
vestibule;  the  scala  tympani  is  shut  off  from  the  vestibule, 
and  terminates  at  the  fenestra  rotunda,  which  is  closed  by 
a  membrane.  Communicating  with  the  scala  tympani  is 
the  aquaeductus  cochleae,  which  opens  on  the  under  surface 
of  the  petrous  portion  of  the  temporal  bone,  and  transmits 

vein  from  the  cochlea  to  the  internal  jugular  vein. 

The  vestibule,  the  semicircular  canals,  and  the  scalae  of 
he  cochlea  are  lined  with  a  delicate  fibro-serons  membrane, 
which  secretes  a  thin  fluid  called  the  liquor  Cotunnii. 

The  MEMBRANOUS  LABYRINTH  is  composed  of  sacs,  over 
which  the  auditory  nerve  is  expanded,  and  which  contain  a 
fluid  called  the  liquor  Scarpae ;  these  sacs  are  two  in  number, 
he  utricle  and  the  saccule,  and  are  a  perfect  counterpart, 
n  form,  of  the  vestibule  and  semicircular  canals.  The 
utricle  is  situated  in  the  posterior  and  upper  part  of  the 
vestibule,  opposite  the  fovea  semi-elliptica  in  the  roof. 
The  saccule  is  smaller  than  the  utricle,  and  is  placed  in 
front  of  the  latter,  in  the  hollow  of  the  fovea  hemispherica. 
The  membranous  tubes  for  the  semicircular  canals  are  pro- 
longations from  the  utricle.  In  these  sacs  will  be  found 
two  small  calcareous  concretions,  called  otoconites.  The 
membranous  labyrinth  floats  in  the  liquor  Cotunnii. 

The  auditory  nerve  divides  into  two  branches  in  the 
meat  us  auditorius  interims,  called  the  cochlear  and  the  ves- 
tibular. 

The  cochlear  branch  enters  by  numerous  filaments  at  the 
base  of  the  modiolus,  and  these,  bending  outward,  are  dis- 
tributed upon  the  lamina  spiralis. 

The  vestibular  branch  divides  into  three  filaments,  one  of 
which  goes  to  the  utricle  and  to  the  membranous  labyrinth 
in  the  ampulla  of  the  superior  and  horizontal  canals ;  the 
second  to  the  saccule,  and  the  third  to  the  membrane  in 
the  ampulla  of  the  oblique  canal. 

The  internal  ear  is  supplied  by  the  internal  auditory 
artery,  a  minute  branch  of  the  basilar  artery,  which  enters 
the  internal  meatus  with  the  auditory  nerve,  and  divides  into 
two  branches,  one  for  the  cochlea  and  one  for  the  vestibule. 


PART    SECOND. 

ANATOMY  OF  THE  UPPER  EXTREMITY, 
THORAX,  AND  BACK. 

.  DISSECTION  I. 

PECTORAL  AND  DELTOID  REGION. 

A  large  block  is  to  be  placed  under  the  subject  so  that  the  scapulae 
shall  rest  upon  it;  the  arm  should  extend  at  an  obtuse  angle  with  the 
body;  the  dissector  stands  upon  its  inner  side.  An  incision  is  to  be 
made,  commencing  at  the  third  rib  (a  longitudinal  incision  along  the 
median  line  of  the  sternum  is  supposed  to  have  been  already  made, 
when  the  subject  was  injected),  and  continued  in  a  straight  line  to 
about  the  middle  of  the  arm.  The  two  flaps  of  skin  thus  marked 
out,  with  the  fat  and  cellular  tissue  beneath,  are  then  to  be  suc- 
cessively reflected  upward  to  the  clavicle,  and  downward  to  the  limits 
of  the  origin  of  the  pectoralis  major.  This  dissection  brings  the  fol- 
lowing parts  into  view  :  — 

The  PECTORALIS  MAJOR  MUSCLE  arises  from  the  sternal 
half  of  the  clavicle,  half  of  the  sternum  in  its  whole 
length,  the  cartilages  of  all  the  true  ribs,  except  the  last, 
and  from  the  aponeurosis  of  the  external  oblique  muscle 
of  the  abdomen  ;  from  which  a  muscular  slip  is  occasion- 
ally added,  which  slip  may  continue  separately  from  the 
pectoralis,  and  have  a  distinct  insertion  into  the  humerus. 
From  this  origin  the  fibres  converge  to  form  a  flat  tendon, 
inserted  into  the  external  ridge  of  the  bicipital  groove  of 
the  humerus,  with  this  peculiarity,  viz:  that  the  fibres 
are  rolled  upon  themselves,  in  such  a  way  that  those  of 
the  upper  portion  of  the  muscle  are  inserted  into  the  lower 
part  of  the  ridge,  and  those  of  the  lower  portion  into  the 
upper  part.  That  part  of  the  muscle  arising  from  the 
clavicle  is  separated  from  that  arising  from  the  sternum 
by  a  cellu)a¥  iiitefsp&ce,  tlie^ize  of  wfriQh,,  as  well  as  the 
extent  of  fctiv&Qp'  qecjjpiecl  -by  t'tie'  stqrnyJ  .origin,  varies 
acco 
ciation 


nt  of  fctivQp'  qecjpiecl  -by  ttie  stqrnyJ  .origin,  varies 
rding  tp  tjie  muscular  development,  or  degree  of  ema- 
ion I/resent  ''I,  by  ivu-h  iml'viciual  subject.     Near  the 


PECTORAL    AND    DELTOID    REGION.  101 

sternal  origin,  the  pectoralis  major  is  perforated  by  a  num- 
ber of  arterial  twigs  which  come  from  the  internal  mam- 
mary artery,  and,  piercing  the  intercostal  spaces,  supply 
the  muscle  and  the  integument. 

The  mammary  gland  will  have  been  removed  with  the  integument; 
it  is lo  be  examined  by  removing  the  fascia  and  cellular  tissue  cover- 
ig  its  base.     The  tubuli  of  the  nipple  may  be  demonstrated  by  the 
insinuation  of  a  bristle  into  their  orifices. 

The  MAMMARY  GLAND  rests  upon  the  pectoralis  major 
luscle,  and  is  separated  from  it  only  by  a  layer  of  fascia, 
[n  the  male  subject  the  gland  is  rudimentary;  in  the  female 
it  varies  in  size  and  development.  It  consists  of  lobules 
md  lobes,  from  which  issue  lactiferous  ducts,  connected 
)gether  by  fibrous  and  adipose  tissue.  The  nipple  is  a 
uiical  prominence  projecting  from  the  centre  of  the  gland, 
at  which  open  the  tubuli  galactophori,  about  twenty  in 
number,  formed  by  the  union-  of  the  converging  lactiferous 
ducts.  The  nipple  is  surrounded  by  an  areola  or  colored 
ring,  the  shade  of  which  is  influenced  by  complexion,  and 
upon  which  numerous  papillae  will  be  noticed. 

The  pectoralis  major  and  the  deltoid  muscles  are  sepa- 
rated from  each  other  by  a  groove  in  which  lies  the  cephalic 
vein,  ascending  from  the  elbow,  and  an  artery,  the  descend- 
ing branch  of  the  thoracica  acromialis. 

The  deltoid  muscle  covers  the  shoulder  and  cannot  be  exposed  in 
its  totality  until  the  subject  be  turned  upon  its  face.  It  is  composed 
of  coarse  muscular  bundles,  difficult  of  dissection  from  the  impossi- 
bility of  making  them  tense ;  this  is  best  effected  by  bringing  the  arm 
down  to  the  side  and  rotating  it  firmly  inward. 

* 

The  DELTOID  MUSCLE  arises  from  the  external  third  of 
the  clavicle,  from  the  lower  border  of  the  acromion  process, 
and  from  the  inferior  border  of  the  spine  of  the  scapula,  as 
far  as  the  triangular  space  which  terminates  it,  and  is 
inserted  into  the  rough  triangular  eminence  on  the  outer 
aspect  of  the  shaft  of  the  humerus.  The  anterior  fibres 
cover  the  tendon  of  the  pectoralis  major  and  are  in  contact 
with  the  upper  part  of  the  biceps ;  posteriorly  they  are 
bound  down  by  fascia.  This  muscle  covers  the  convex 
head  of  the  humerus  and  the  insertions  of  the  scapular 
muscles  into  the  tuberosities  of  that  bone.  A  bursa,  more 
or  less  apparent,  lies  between  these  tendons  and  the  under 
surface  of  the  deltoid  muscle. 

9* 


102       ANATOMY    OF    UTPER    EXTREMITY,    ETC. 

The  dissection  of  these  two  muscles  completed,  the  pectoralis  major 
may  be  divided  through  its  middle  and  the  two  ends  reflected  ;  in  so 
doing,  some  offsets  of  the  thoracica  acromialis  and  superior  thoracic 
arteries  will  be  cut  across,  as  well  as  the  short  thoracic  nerve,  given 
off  from  the  brachial  plexus  just  below  the  clavicle.  On  clearing 
away  the  fat  and  cellular  tissue,  the  pectoralis  minor  muscle  comes 
into  view. 

The  PECTORALIS  MINOR  MUSCLE  arises  by  three  distinct 
tongues  from  the  third,  fourth,  and  fifth  ribs,  and  is  in- 
serted into  the  anterior  border  of  the  coracoid  process  of 
the  scapula,  in  common  with  the  short  head  of  the  biceps 
and  coraco-brachialis  muscles. 

Connected  with  the  upper  border  of  the  pectoralis  minor 
and  inserted  into  the  first  rib  and  the  coracoid  process,  and 
to  the  clavicle  between  these  points,  is  a  dense  fascia  called 
the  costo-coracoid  membrane.  When  this  is  removed  it 
will  be  found  to  have  concealed  a  small  muscle  called  the 
subclavius. 

The  SUBCLAVIUS  MUSCLE  arises  by  a  short  thick  tendon 
from  the  cartilage  of  the  first  rib ;  its  fibres  are  directed 
outward  and  are  inserted  into  the  under  surface  of  the 
clavicle  for  more  than  half  its  length;  this  muscle  receives 
a  muscular  nerve  from  the  brachial  plexus  behind  the 
clavicle. 

AXILLA. 

The  dissection  pursued  thus  far  will  have  exposed  a 
large  space  filled  with  fat,  cellular  tissue  and  lymphatic 
glands,  lying  behind  the  pectoralis  minor,  and  through 
which  pass  the  axillary  artery,  with  its  vein,  and  the  bra- 
chial plexus  of  nerves;  this  space  is  called  the  AXILLA. 
The  pectoralis  minor  forms  but  a  small  part  of  its  anterior 
boundary,  which  is  completed  by  the  pectoralis  major;  the 
posterior  boundary  is  formed  by  the  flat  tendon  of  the 
latissimus  dorsi,  by  the  teres  major  and  sub-scapularis 
muscles;  internally  it  is  limited  by  the  serratus  magnus 
and  externally  by  the  biceps  and  coraco-brachialis  muscles. 

Keeping  the  arm  well  extended,  patience  and  a  little  ingenuity  in 
hooking  aside  the  branches  of  arteries  and  filaments  of  nerves,  to 
make  room  for  the  scalpel  to  reach  others,  will  accomplish  the  display 
of  the  axillary  artery  and  its  branches.  The  brachial  plexus  of  nerves, 
surrounding  the  artery,  will,  to  a  certain  extent,  be  prepared  in  this 
dissection.  Veins  which  it  is  impossible  to  avoid  dividing  should  be 
tied,  so  that  the  blood  oozing  from  them  may  neither  soil  nor  obscure 
the  dissection.  In  a  locality  like  this,  the  dissector  will  find  the 
scissors  a  most  effective  and  serviceable  instiument. 


AXILLA.  103 

The  AXILLARY  ARTERY  is  that  portion  of  the  artery 
destined  to  the  upper  extremity,  intervening  between  the 
subclavian  and  brachial  arteries,  and  extending  from  the 
outer  border  of  the  first  rib  to  the  lower  margin  of  the 
tendon  of  the  latissimus  dorsi  and  teres  major;  it  passes 
through  the  axilla  nearer  to  its  anterior  than  its  posterior 
border.  The  axillary  vein  lies  in  front  and  at  the  inside 
of  the  artery,  and  is  formed  by  the  union  of  the  basilic 
vein  of  the  arm  and  the  venae  comites  of  the  brachial 
artery ;  it  receives  the  cephalic  vein  near  the  clavicle,  and 
smaller  veins,  from  the  muscles,  or  which  accompany  the 
branches  of  the  axillary  artery,  enter  it  at  various  parts  of 
its  course. 

The  BRACHIAL  PLEXUS,  formed  from  the  anterior 
branches  of  the  last  four  cervical,  and  the  first  dorsal 
nerves  (p.  59),  lies  upon  the  outer  side  of  the  axillary 
artery  at  its  upper  part;  lower  down  it  surrounds  the 
rtery,  giving  off*  its  branches  at  various  points.  Some  of 
;hese  will  be  described  with  the  dissection  of  the  arm ; 
those  which  are  given  to  the  thoracic  and  scapular  mus- 
cles will  now  be  enumerated,  though  a  further  reference  to 
them  will  be  made  with  the  dissection  of  those  muscles. 
These  nerves  are  six  in  number,  viz: — 


Superior  Muscular,  Supra-scapular, 

Short  Thoracic,  Sub-scapular, 

Long  Thoracic,  Inferior  Muscular. 


The  superior  muscular  supply  the  subclavius,  rhomboidei,  and 
levator  anguli  scapulae  muscles;  they  are  branches  of  the  fifth  cer- 
vical nerve,  and  are  given  off  from  the  plexus  behind  the  clavicle. 

The  short  thoracic,  two  in  number,  supply  the  pectoralis  major  and 
minor  muscles ;  they  are  given  off  from  the  plexus  at  a  point  parallel 
with  the  clavicle. 

The  long  thoracic  passes  down  behind  the  axillary  vessels  and  plexus, 
ramifies  on  the  side  of  the  thorax,  and  is  distributed  to  the  fibres  of 
the  serratus  magnus  muscle  exclusively;  it  is  a  branch  of  the  fourth 
and  fifth  cervical  nerves. 

The  supra-scapular  passing  outward,  goes  through  the  supra-scapu- 
lar notch,  and  supplies  the  supra-  and  iufra-spinatus  muscles ;  it  is  a 
branch  of  the  fifth  cervical  nerve. 

The  sub-scapular  are  two  in  number,  and  are  both  distributed  to  the 
sub-scapularis  muscles;  one  of  them  comes  from  the  plexus  above  the 
clavicle,  and  the  other  from  the  posterior  aspect  of  the  plexus  within 
the  axilla. 

The  inferior  muscular  consist  of  one  or  more  branches,  distributed 
to  the  teres  major  and  latissimus  dorsi  muscles;  they  are  given  off 
from  the  lower  part  of  the  plexus. 


104        ANATOMY    OP     UPPER    EXTREMITY,    ETC, 


The  axillary  artery  gives  off  seven  branches  which  van 
extremely,  however,  as  to  their  precise  points  of  origin. 
In  one  case  in  ten,  it  gives  off  a  larger  branch  than  usual, 
and  this  may  be  either  the  radial,  the  ulnar,  the  interosse- 
ous,  or  a  trunk  from  which  arise  the  sub-scapular,  the  cir- 
cumflex, and  profunda  arteries.  The  regular  axillary 
branches  are — 


Thoracica  Acromialis, 
Superior  Thoracic, 
Inferior  Thoracic, 


Thoracica  Axillaris, 
Sub-scapular, 

Anterior  and  Posterior  Cir- 
cumflex. 


The  thoracica  acromialis  emerges  in  the  space  above  the  border  of 
the  pectoralis  minor  muscle  and  divides'  into  branches,  which  are 
directed  inward  to  the  two  pectoral  muscles  and  outward  to  the 
deltoid  ;  from-the  deltoid  set  a  small  twig,  called  the  inferior  acromial, 
passes  down  beside  the  cephalic  vein  in  the  interspace  between  the 
pectoralis  major  and  deltoid  muscles. 

The  superior  thoracic  (sometimes  given  off  by  the  preceding  artery), 
passes  along  the  upper  border  of  the  pectoralis  minor,  distributing 
branches  to  the  pectoralis  major  and  mammary  gland,  and  inosculates 
with  the  branches  of,  the  internal  mammary,  emerging  between  the 
costal  cartilages  near  the  sternum. 

The  inferior  thoracic  or  external  mammary  (sometimes  given  off  from 
the  thoracica  acromialis  or  the  sub-scapular),  passes  along  the  lower 
border  of  the  pectoralis  minor  and  is  distributed  to  the  pectoralis 
major,  the  mammary  gland,  and  the  serratus  magnus,  anastomosing 
with  the  superior  thoracic  and  with  external  branches  of  the  inter- 
costal arteries. 

The  thoracica  axillaris  is  a  small  artery  (arising  frequently  from 
one  of  the  other  branches)  distributed  to  the  nerves  and  arteries  of 
the  axilla. 

The  sub-scapular  is  the  largest  branch  of  the  axillary  artery ;  it 
passes  along  the  lower  border  of  the  sub-scapularis  muscle,  supplying 
that  muscle  as  well  as  those  of  the  lower  border  of  the  scapula,  and 
gives  off  a  dorsal  branch  which,  passing  under  its  edge,  is  distributed 
to  the  posterior  surface  of  that  bone  ;  this  artery  and  its  branches 
inosculate  with  the  posterior  and  supra-scapular  arteries,  branches  of 
the  subclavian. 

To  obtain  a  view  of  the  two  remaining  branches,  the  deltoid  muscle 
must  be  divided  and  its  two  ends  reflected  ;  in  so  doing  a  few  small 
branches  of  the  posterior  circumflex  artery  will  be  cut  across. 

The  anterior  circumflex  is  a  small  artery,  passing  beneath  the  coraco- 
brachialis  muscle  and  the  short  head  of  the  biceps,  to  wind  around 
in  front  of  the  head  of  the  humerus  :  it  sends  a  small  branch  along 
the  bicipital  groove  to  the  shoulder-joint. 

The  posterior  circumflex,  much  larger  than  the  anterior,  passes  back- 
ward beneath  the  head  of  the  humerus,  giving  branches  to  th( 
shoulder-joint,  and  also,  after  emerging  on  the  other  side  of  the  bout 


FRONT    OF    THE    ARM.  105 

to  the  deltoid  muscle.  These  two  last-named  arteries,  together  with 
the  profunda,  are  frequently  given  off  from  a  common  trunk,  instead 
of  from  the  axillary  artery. 


DISSECTION  II. 

FRONT    OF    THE    ARM. 

An  incision  is  to  be  made  down  the  middle  of  the  arm,  to  a  short 
distance  below  the  bend  of  the  elbow,  care  being  taken  not  to  divide 
the  cutaneous  veins  or  nerves,  which  near  the  elbow  are  quite  super- 
iicial.  The  anterior  portion  of  the  arm  is  to  be  cleared  from  cellular 
tissue,  the  numerous  nerves,  arteries,  and  veins  being  carefully 
managed  while  the  muscles  are  isolated  from  each  other  and  the 
surrounding  parts.  The  insertions  of  the  biceps  and  brachialis 
anticus  muscles  cannot  be  examined  until  a  subsequent  stage  of  the 
dissection. 

Iii  preparing  the  front  of  the  arm  two  large  veins  will 
have  been  traced  from  the  elbow  upward;  these  are  the 
cephalic  and  basilic. 

The  CEPHALIC  VEIN  ascends  upon  the  outer  side  of  the 
biceps  muscle  to  the  space  between  the  pectoralis  major 
and  deltoid  muscles,  along  which  it  passes  to  terminate 
beneath  the  clavicle  in  the  axillary  vein. 

The  BASILIC  VEIN,  superficial  at  the  lower  part,  pierces 
the  fascia  near  the  middle  of  the  arm,  and,  accompanying 
the  artery  at  its  inner  side,  becomes,  in  the  axilla,  the 
axillary  vein.1 

The  BICEPS  MUSCLE  constitutes  the  bulk  of  the  arm  in 
front.  It.  arises  by  two  heads,  a  short  and  a  long;  the 
short  head,  in  common  with  the  coraco-brachialis,  arises 
from  the  coracoid  process  of  the  scapula ;  the  long  head 
arises  by  a  round  and  slender  tendon  from  the  upper 
margin  of  the  glenoid  cavity  of  the  scapula ;  this  passes 
over  the  head  of  the  humerus  through  a  special  synovial 
sheath  and  enters  the  bicipital  groove  ;  emerging  from  this, 
it  expands  into  a  broader  tendon  from  which  the  muscular 
fibres  take  their  origin.  These  two  heads  uniting  form  the 
belly  of  the  muscle,  which,  terminating  in  a  flattened  tendon, 

1  The  first  two  letters  of  the  word  "biceps,"  that  being  the  muscle 
with  which  this  vein  is  in  relation,  will  give  the  student  a  mnemonic 
aid  to  retain  in  his  mind  the  relative  position  of  the  basilic  and 
cephalic  veins.  (B.  I.  basilic,  internal.) 


106        ANATOMY    OP    UPPER    EXTREMITY,    ETC. 

/ 

penetrates  between  the  muscles  of  the  forearm  to  be  ii 
serted  into  the  tubercle  of  the  radius.  An  aponeurotic 
expansion  continuous  with  the  fascia  of  the  forearm,  is 
given  off  at  the  elbow  from  the  outer  side  of  the  tendon  of 
insertion,  protecting  the  brachial  artery  which  lies  just 
beneath  it.  The  biceps  sometimes  has  &'third  head,  which 
consists  of  a  bundle  of  muscular  fibres  from  the  front  of  the 
humerus,  usually  connected  with  the  brachialis  anticus,  and 
which  unites  with  the  lower  part  of  the  belly  of  the  muscle 
on  its  inner  side.  Two  or  three  muscular  branches  of  the 
brachial  artery  enter  this  muscle.  The  inner" border  of  the 
biceps,  at  its  middle,  is  the  guide  to  the  brachial  artery, 
which  lies  just  within  its  edge  and  inside  the  median  nerve. 

The  CORACO-BRACHIALIS  MUSCLE  lies  at  the  inside  of  the 
biceps ;  it  arises  from  the  coracoid  process,  between  the 
pectoralis  minor  and  the  short  head  of  the  biceps,  and  is 
inserted  into  a  rough  line  on  the  inner  side  of  the  middle 
of  the  humerus. 

The  BRACHIALIS  ANTICUS  MUSCLE  lies  beneath  the 
biceps  on  the  lower  half  of  the  arm ;  it  arises  from  the 
humerus  by  muscular  fibres  which  embrace  the  insertion  of 
the  deltoid,  and  is  inserted  into  the  coronoid  process  of  the 
ulna.  Its  insertion  cannot  be  fully  seen  until  the  forearm 
is  dissected. 

The  BRACHIAL  ARTERY  extends  from  the  lower  border  of 
the  conjoined  tendons  of  the  latissimus  dorsi  and  teres 
major  to  the  bend  of- the  elbow,  where  it  divides  into  the 
radial  and  ulnar  arteries;  it  lies  along  the  inner  border  of 
the  coraco-brachialis  and  biceps  muscles,  and  is  superficial 
in  nearly  its  whole  extent;  the  basilic  vein  lies  in  front  of 
the  artery  and  the  ulnar  nerve  along  its  inner  side;  the 
median  nerve  lies  first  upon  its  outer  side,  then  crosses  it 
and  descends  to  the  elbow  on  its  inner  side. 

The  normal  condition  of  this  trunk  may  be  varied  by 
what- is  called  its  "high  division;"  that  is,  instead  of 
originating  at  the  usual  point,  the  radial,  ulnar,  or  inter- 
osseous  arteries,  one  or  all,  are  given  off  higher  up,  along 
the  course  of  the  brachial  or  even  of  the  axillary  artery. 
Sometimes  the  radial  and  ulnar,  when  thus  given  off,  are 
connected  by  a  transverse  branch.  Occasionally  the  brachial 
arteiy  descends  with  the  median  nerve  to  a  point  near  the 
inner  condyle,  where  it  turns  around  a  prominence  of  bone1 

1  Called  the  "supra-condyloid  process"  of  the  humerus. 


FRONT    OF    THE    ARM.  107 

which  is  occasionally  present,  and  regains  its  usual  position. 
This  anomaly  is  analogous  to  the  ordinary  distribution  of 
the  vessel  in  some  carnivorous  animals,  in  which  it  passes 
through  a  foramen  in  the  humerus,  a  short  distance  above 
the  inner  condyle. 

The  brachial  artery  has  three  branches. 

Superior  and  Inferior  Profunda, 
Anastomotica  Magna. 

The  superior  profunda  is  given  off  close  below  the  tendon  of  the 
latissimus  dorsi ;  it  passes  under,  and  winds  around  the  humerus,  to 
reappear  in  the  muscular  interspace  on  the  outer  side  of  the  brachialis 
anticus,  where  it  inosculates  with  the  radial  recurrent  artery.  The 
profunda  artery  sends  a  branch  down  the  posterior  aspect  of  the  hu- 
merus, to  the  articulation,  and  this  inosculates  with  the  recurrent 
branch  of  the  posterior  interosseous  artery. 

The  inferior  profunda  is  a  small  branch  given  off  about  the  middle 
of  the  arm;  it  passes  downward,  penetrates  behind  the  inner  condyle, 
and  inosculates  with  the  posterior  ulnar  recurrent.  This  artery  often 
arises  from  the  preceding,  or  is  altogether  wanting. 

The  anastomotica  magna  is  given  off  upon  the  inside  of  the  arm  just 
above  the  elbow;  it  runs  transversely  inward  through  the  inter-mus- 
cular septum  to  the  hollow  between  the  olecranon  and  the  inner  con- 
dyle, where  it  inosculates  with  the  inferior  profunda  and  the  posterior 
ulnar  recurrent  branch.  One  of  its  muscular  offsets  forms  an  arch 
across  the  back  of  the  humerus  with  a  branch  of  the  superior  pro- 
funda. 

If  the  various  branches  into  which  the  brachial  plexus 
of  nerves  divides,  and  which  are  distributed  to  the  arm 
and  forearm,  have  been  carefully  followed  out,  as  far  as 
the  elbow,  in  connection  with  the  previous  dissection,  they 
will  be  found  to  be  seven  in  number,  viz : — 

External  Cutaneous,  Circumflex, 

Internal  Cutaneous,  Musculo-spiral, 

Lesser  Internal  Cutaneous,  Median, 
Ulnar. 

The  EXTERNAL,  or  MUSCULO-CUTANEOUS,  or  PERFORANS 
CASSERII  NERVE,  arises  in  common  with  the  external  head 
of  the  median  nerve;  it  supplies  the  coraco-brachialis, 
which  it  pierces  (hence  its  name  of  perfor ans),  and  the 
biceps  and  brachialis  anticus,  and  passes  between  these  two 
muscles  to  appear  on  the  outer  side  of  the  elbow,  where  it 
divides  into  two  branches,  both  supplying  the  integument, 
the  external  down  to  the  back  of  the  hand,  and  the  internal 
as  far  as  the  wrist  anteriorly. 


108        ANATOMY    OF    UPPER    EXTREMITY,    ETC. 

The  two  following  nerves  are  extremely  liable  to  be  removed  wit 
the  flap  of  integument,  their  small  size  and  superficial  position  It 
ing  to  their  division  as  they  lie  unnoticed  in  the  cellular  tissue. 

The   INTERNAL   CUTANEOUS  NERVE   arises  in   comra< 
with  the  internal  head  of  the  median  nerve ;  it  passes  d 
the  arm  by  the  side  of  the  basilic  vein,  giving  off  cutaneous 
filaments   in  its   course,  and   divides   into  two   principal 
branches,  both  of  which  are  distributed  to  the  integumei 
of  the  forearm  along  its  inner  and  anterior  aspect. 

The  LESSER  INTERNAL  CUTANEOUS  NERVE,  or  NERVE  OF 
WRISBERG,  is  the  smallest  nerve  of  the  arm ;  it  is  found 
inside  of  the  internal  cutaneous  nerve,  and  is  distribute 
to  the  integument  of  the  lower  and  inner  part  of  the  an 
Just  below  the  axilla,  this  nerve  communicates  with  tl 
inter  costo-humeral  nerve,  a  branch  of  the  second  intercosl 
nerve,  stretching  across  from  the  thoracic  parietes  to  tl 
axilla.  A  second  intercosto-humeral  nerve,  from  the  thii 
intercostal,  sometimes  exists. 

The  CIRCUMFLEX  NERVE  is  a  large  trunk  which  cross* 
the  tendon  of  the  sub-scapularis  to  pass  directly  underneath 
and  around  the  head  of  the  humerus,  in  company  with  the 
posterior  circumflex  artery;  it  gives  branches  to  the  deltoid, 
the  neighboring  integument,  and  to  all  the  muscles  of  the 
scapular  region.  Its  sudden  turn,  and  the  shortness  of  its 
trunk  before  disappearing  behind  the  humerus,  sometimes 
embarrass  the  dissector  in  his  search  for  this  branch  of  th( 
brachial  plexus. 

The  MUSCULO-SPIRAL  NERVE  arises  in  common  with  th( 
circumflex;  it  passes  behind  the  brachial  artery,  and  winds 
spirally  round  the  humerus,  in  company  with  the  superi< 
profunda  artery,  to  reach  the  outer  side  of  the  arm,  whei 
it  lies  deep  between  the  brachialis  anticus  and  supinatc 
longus  muscles,  and  divides  into  two  branches — radial  ai 
posterior  interosseous. 

The  MEDIAE  NERVE  arise*s  by  two  heads,  which,  in  tl 
axilla,  embrace  the  brachial -artery;  these  form  a  trunk  oi 
large  size  which  lies  at  first  on  the  outer  side  of  the  vessel, 
afterward  on  its  inner  side,  and  descends  without  any 
branches  to  the  bend  of  the  elbow,  where  it  gives  off  some 
muscular  branches  and  the  anterior  interosseous  nerve  ;  it 
then  continues  down  the  forearm  to  the  hand. 

The  ULNAR  NERVE  arises  in  common  with  the  internal 
head  of  the  median,  and  internal  cutaneous  nerves,  and  de- 
scends without  branches  upon  the  inner  side  of  the  brachial 
artery,  to  the  hollow  between  the  inner  condyle  and  olecra- 


;: 


BEND     OF     THE     ELBOW.  109 

non,  where  it  gives  off  muscular  and  articular  branches,  and 
continues  down  the  ulnar  side  of  the  forearm  to  the  hand. 

BEND  OF  THE  ELBOW. 

The  veins  at  the  front  of  the  elbow  should  be  studied, 
with  reference  to  the  operation  of  venesection.  A  ligature, 
placed  high  up  around  the  arm  of  a  living  person,  affords, 
in  many  respects,  a  better  opportunity  for  studying  them 
than  is  found  upon  the  dead  subject.  They  are  generally 
irregular,  and  rarely  correspond  with  the  description  given 
in  books ;  certain  relationships  between  them  and  the  ar- 
tery and  nerves,  should,  however,  be  carefully  noted. 

Three  superficial  veins  return  the  blood  from  the  fore- 
arm— viz:  RADIAL,  ULNAR,  and  MEDIAN — the  situations  of 
which  are  indicated  by  their  names.  The  median  vein 
divides  at  the  elbow  into  two  short  branches,  which  unite 
respectively  with  the  ulnar  and  radial  veins ;  the  internal 
branch  is  called  the  median  basilic,  the  external  the  median 
cephalic ;  the  basilic  vein  being  the  continuation  of  the 
median  basilic  and  ulnar,  and  the  cephalic  of  the  median 
cephalic  and  radial  veins.  The  disposition  of  these  veins 
at  the  elbow  may  be  compared  to  the  letter  M ;  the  middle 
angle  of  that  letter  representing  the  division  of  the  median 
vein,  the  superior  lateral  angles  corresponding  to  the  com- 
mencement of  the  cephalic  and  basilic  veins,  formed  by  the 
union  of  the  median  cephalic  and  median  basilic  with  the 
radial  and  ulnar  veins,  which  are  represented  by  the  limb 
upon  each  side  of  the  letter. 

The  MEDIAN  BASILIC  VEIN  crosses  the  brachial  artery, 
being  separated  from  it  only  by  the  aponeurotic  slip  given 
to  the  fascia  of  the  forearm  from  the  tendon  of  the  biceps. 
Branches  of  the  internal  cutaneous  nerve  pass  both  in  front 
and  behind  this  vein. 

The  MEDIAN  CEPHALIC  VEIN,  smaller  than  the  median 
basilic,  passes  outward  along  the  fold  of  the  elbow,  some- 
what less  superficially ;  the  branches  of  the  external  cuta- 
neous nerve  pass  beneath  the  vein. 

Notwithstanding  that,  in  bleeding,  the  operator  usually 
selects  the  largest  vein,  it  will  be  seen  that  the  median 
cephalic  presents  the  more  favorable  conditions  than  the 
median  basilic,  being  awray  from  the  artery  and  above  the 
nerve,  while  the  latter,  though  ordinarily  the  largest,  is  not 
only  almost  in  contact  with  the  artery,  but  surrounded  by 
10 


110        ANATOMY    OF    UPPER    EXTREMITY,   ETC. 

nerves.  This  dissection  will  at  least  show  the  importance 
of  exploring  the  arm  for  the  pulsations  of  the  artery  with 
reference  to  its  -relation  to  the  vein,  whichever  it  may  be 
that  it  is  proposed  to  open,  if  the  dangers  of  traumatic 
aneurism  would  be  avoided. 

In  the  dissection  of  the  elbow,  a  lymphatic  gland  will  be 
found  with  a  considerable  degree  of  constancy,  just  above 
the  inner  condyle;  practically  important,  as  being  some- 
times enlarged  and  inflamed  from  wounds  or  ulcerations  of 
the  hands  or  fingers,  and  almost  constantly  so  in  cases  of 
constitutional  syphilis. 


DISSECTION  III. 

STERNAL  REGION. 

The  further  dissection  of  the  upper  extremity  is  now  to  l>e  relin- 
quished until  the  thorax  and  its'  contents  have  been  examined.  It 
should  be  carefully  wrapped  in  a  bandage  and  kept  constantly  damp 
until  its  dissection  is  resumed. 

The  anterior  wall  of  the  thorax  is  to  be  removed  by  dividing  upon 
each  side  the  costal  cartilages  and  intercostal  muscles,  close  to  the 
ribs.  If  the  lungs  be  free  from  adhesions,  and  the  pleural  cavity  has 
not  yet  been  opened,  the  student  will  hear,  as  he  first  opens  into  it, 
the  whistle  of  the  air  as  it  enters  the  vacuum  previously  existing,  and 
will  see  the  lungs  collapse  under  the  atmospheric  pressure  to  which 
they  are  then  first  subjected.  If  the  dissection  of  the  muscles  attached 
to  the  upper  part  of  the  sternum  and  clavicle  is  completed,  the  whole 
of  the  sternum  may  be  removed  ;  otherwise  a  portion  must  be  left  by 
sawing  it  across,  an  inch  below  its  summit.  The  segment  included  in 
the  incisions  made  is  to  be  lifted,  first  by  one  and  afterward  by  both 
of  its  lower  angles,  and  the  cellular  and  muscular  tissues  divided 
which  attach  it  to  the  parts  beneath.  Its  separation  at  the  first  rib 
and  from  the  clavicle  is  a  little  difficult,  unless  properly  performed  ; 
the  knife,  as  it  approaches  the  first  rib,  should  be  directed  obliquely 
outward  till  its  cartilage  is  divided,  then  turning  at  right  angles  to 
this  incision,  it  is  to  be  carried  inward,  gradually  describing  a  curve 
with  its  concavity  outward,  through  the  sterno-clavicular  articulation. 
Every  autopsy  which  the  student  attends  affords  him  opportunity  of 
studying  nearly  all  the  parts  about  to  be  described. 

Upon  the  inside  of  the  plastron,  as  the  segment  thus 
removed  is  called,  beneath  a  layer  of  cellular  tissue,  will 
be  found  a  muscle  called  the  TRIANGULARIS  STERNI;  it  arises 
from  the  sides  of  the  sternum  as  high  as  the  third  cartilage, 
from  the  ensiform  cartilage,  and  sternal  extremities  of  the 


LIGAMENTS    OF    STERNUM,    ETC.  Ill 

lower  three  or  four  costal  cartilages,  and  is  inserted  by 
fleshy  dictations  into  the  cartilages  of  the  third,  fourth, 
fifth,  and  sixth  ribs,  and  often  into  that  of  the  second. 
This  muscle  varies  frequently  in  its  extent  and  points  of 
attachment. 

The  INTERNAL  MAMMARY  ARTERY,  detached  by  this  sec- 
tion from  its  connection  with  the  subclavian,  descends  upon 
each  side  of,  and  about  half  an  inch  from  the  sternum ;  it 
gives  off  the  anterior  inter  costals,  which  turn  outward  in  the 
upper  five  or  six  intercostal  spaces  to  inosculate  with  the 
aortic  intercostals,  and  furnish  the  branches  which  perforate 
the  intercostal  muscles,  close  to  the  sternum,  to  be  dis- 
tributed to  the  pectoralis  major  muscle  and  the  integument 
of  the  thorax.  A  small  branch,  the  comes  nervi  phrenici, 
given  off  as  soon  as  the  artery  enters  the  chest,  and  which 
descends  to  the  diaphragm  with  the  phrenic  nerve,  will  have 
been  cut  off  and  left  behind.  Some  small  twigs,  called 
mediastinal  and  pericardiac,  will  also  be  found.  At  the 
interval  between  the  sixth  and  seventh  ribs,  it  gives  off  a 
large  branch  called  the  musculo-phrenic,  which  winds  along 
the  attachment  of  the  diaphragm  to  the  ribs,  and  supplies 
the  lower  intercostal  spaces.  The  termination  of  the  inter- 
nal mammary  is  sometimes  called  the  superior  epigastric 
artery;  it  passes  downward  between  the  rectus  muscle  and 
its  sheath,  and  inosculates  with  the  epigastric  branch  of 
the  external  iliac.  This  artery  occasionally  gives  off  on 
both  sides,  from  near  its  origin,  a  good-sized  branch,  which 
might  be  called  an  internal  thoracic  artery;  it  traverses 
the  ribs  near  their  middle,  to  the  fifth  intercostal  space, 
where  it  becomes  an  intercostal  artery. 

LIGAMENTS  OF  THE  STERNUM,  AND  COSTAL  CARTILAGES. 

The  two  bones  of  the  sternum  are  connected  by  an  in- 
tervening fibro-cartilage.  Upon  the  anterior  and  posterior 
surfaces  their  union  is  strengthened  by  longitudinal  fibres, 
which  blend  with  other  similar  fibres  radiating  from  the 
costal  cartilages,  and,  in  front,  with  the  sternal  tendinous 
origins  of  the  pectoral  muscles.  The  anterior  aspect  of  the 
sternum  is  therefore  rough  and  fibrous,  while  the  posterior 
is  comparatively  smooth. 

The  cartilages  of  the  ribs,  received  into  the  lateral  fossa3 
of  the  sternum,  are  each  provided  with  a  synovial  mem- 
brane, and  held  in  place  by  radiating  ligamentous  fibres, 
anteriorly  and  posteriorly,  which  blend  with  those  of  the 


112        ANATOMY     OF    UPPER    EXTREMITY,    ETC. 

opposite  side,  and,  in  front,  with  the  tendinous  origins  of 
the  pectoral  muscles. 

The  costal  cartilages  are  held  in  connection  with  the 
anterior  extremities  of  the  ribs  only  by  the  periosteum. 

The  cartilages  of  the  sixth,  seventh,  and  eighth  ribs 
articulate  by  their  lower  borders  with  the  upper  borders  of 
the  cartilages  next  below.  The  articulation  is  lined  with  a 
synovial  membrane,  and  the  connection  is  maintained 
ligamentous  fibres.  The  cartilage  of  the  seventh,  and 
times  also  of  the  sixth  rib,  is  attached  to  the  ensiform  car- 
tilage by  a  band  of  variable  size,  called  the  costo-xiphou 
ligament. 

ANTERIOR  MEDIASTINUM. 

The  space  left  between  the  two  pulmonary  cavities  is 
called  the  MEDIASTINUM;  it  extends  from  the  summit  of 
the  chest  to  the  diaphragm,  and  from  the  sternum  to  the 
spine.  Although  there  is  but  one  mediastinum,  the  terms 
anterior  and  posterior  have  been  applied  respectively  to 
the  portions  in  front  of  and  behind  the  pericardium. 

The  ANTERIOR  MEDIASTINUM  contains  a  quantity  of  loose 
cellular  tissue,  the  remains  of  the  thymus  gland*  the  peri- 
cardium and  heart,  arch  of  the  aorta,  superior  vena  cava, 
with  the  right  and  left  innominate  veins,  bifurcation  of  the 
trachea,  pulmonary  veins  and  arteries,  and  phrenic  nerves. 

The  THYMUS  GLAND,  in  the  adult  subject,  consists  only 
of  a  small  quantity  of  cellulo-adipose  tissue;  sometimes  no 
trace  of  it  is  to  be  found.  In  children  under  two  years  of 
age  it  is  an  organ  of  considerable  size,  reaching  from  just 
below  the  thyroid  bod}T,  half-way  to  the  diaphragm. 

The  PHRENIC  NERVES,  the  upper  parts  of  which  will  have 
been  observed  in  the  dissection  of  the  neck  (p.  56),  where 
they  arise  by  filaments  from  the  third,  fourth,  and  fifth  cer- 
vical nerves,  and  descend  upon  the  scalenus  anticus  muscle 
to  enter  the  chest,  will  here  be  seen  passing  through  the 
anterior  mediastinum  upon  the  sides  of  the  pericardium, 
between  it  and  the  pleura.  Their  course  can  be  traced  with- 
out dissection,  descending  to  the  diaphragm,  upon  which 
they  ramify  beneath  the  pleura,  the  two  nerves  anasto- 
mosing on  the  under  surface  of  the  muscle  by  filaments, 
which  pass  through  its  fibres. 

The  VENJE  INNOMINATE  are  found  in  the  upper  part  of 
the  mediastinum.  They  are  formed  on  each  side  by  the 
subclavian  and  internal  jugular  veins;  the  union  of  the 


ANTERIOR    MEDIASTINUM.  113 

two  venae  mnominatae  constitutes  the  superior  vena  cava. 
{Sometimes  the  innominate  veins  are  not  united  into  one, 
but  descend  separately  to  the  heart,  where  both  have  dis- 
tinct openings  in  the  right  auricle  (p.  55). 

The  SUPERIOR  VENA  CAVA  is  about  three  inches  in  length ; 
it  passes  downward,  piercing  the  pericardium,  to  enter  the 
upper  part  of  the  right  auricle  of  the  heart.  Before  enter- 
ing the  pericardium,  it  receives  the  vena  azygos  major. 

If  the  subject  being  dissected  has  been  injected  from  the 
aorta,  the  pericardium  will  have  been  laid  open,  in  order  to 
perform  that  operation. 

The  PERICARDIUM  is  the  sac  containing  the  heart;  it  con- 
sists of  a  fibrous  external  and  a  serous  internal  layer.  The 
fibrous  layer  is  attached  to  the  great  vessels  of  the  heart 
above,  and  to  the  diaphragm  below.  The  serous  layer  in- 
vests the  heart,  and  is  then  reflected  from  it  to  the  fibrous 
layer,  thus  forming  a  shut  sac,  as  a  serous  membrane  always 
does,  with  the  heart  in  reality  lying  outside  of  it.  The 
student  has  only  to  imagine  this  sac  a  globular  one  to  see 
lat  the  heart,  by  making  a  protrusion  into  its  cavity,  will 
ot  only  be  covered  by  a  serous  surface,  but  lie  in  contact 
with  another  which  is  free  and  external  to  it. 

The  HEART  occupies  an  oblique  position  in  the  chest,  its 
apex  pointing  to  the  space  between  the  fifth  and  sixth  ribs, 
two  or  three  inches  from  the  sternum,  and  its  base  toward 
the  right  shoulder.  It  should  be  observed  that  the  apex  is 
formed  by  the  left  ventricle,  as,  when  the  organ  is  opened 
and  emptied  of  blood,  this  is  not  so  apparent.  The  under 
side  of  the  heart  is  flattened,  and  rests  lipon  the  diaphragm ; 
its  upper  surface  is  rounded.  It  may  be  remarked  that  the 
terms  "right"  and  "left"  ventricle  might  well  be  dispensed 
with,  and  the  terms  "anterior"  and  "posterior"  substituted 
in  their  place.  Monro  states  that  the  habit  of  describing 
the  two  sides  as  right  and  left  arose  from  the  fact  that  the 
earlier  dissections  were  made  upon  animals,  in  whom  the 
position  of  the  ventricles  differs  from  that  in  man,  and  is 
in  fact  right  and  left. 

By  lifting  the  heart,  and  pulling  it  to  either  side,  the  vessels  ema- 
nating from  or  entering  it  will  be  made  apparent,  and  are  to  be 
examined  both  within  the  pericardium  and  after  tlieir  exit  from  it. 
On  the  outside  a  little  dissection  will  be  necessary  to  separate  them, 
from  one  another,  and  from  the  bronchial  glands  and  cellular  tissue 
which  surround  them;  part  of  the  pericardium  must  be  cut  away. 

10* 


114    ANATOMY  OF  UPPER  EXTREMITY,  ETC. 

The  superior  vena  cava  will  be  seen  entering  the  peri- 
cardium and  joining  the  upper  part  of  the  right  auricle. 

The  INFERIOR  YENA  CAVA  enters  the  inferior  part  of  the 
right  auricle  as  soon  as  it  passes  through  the  diaphragm 
and  pericardium,  holding  the  root  of  the  heart  downward, 
and  giving  the  organ  the  oblique  position  peculiar  to  it. 

The  PULMONARY  VEINS  are  four  in  number,  two  for  each 
side;  those  upon  the  right  side  are  longer  than  the  others, 
and  emerge  from  the  right  lung  in  front  of  the  pulmonary 
artery;  they  pass  beneath  the  inferior  vena  caA^a  and  enter 
the  left  auricle.  The  two  left  pulmonary  veins  reach  the 
same  cavity  after  a  shorter  course,  passing  in  front  of  the 
descending  aorta.  These  vessels,  though  carrying  arterial 
blood,  are  called  veins,  because,  like  veins,  they  bring  the 
blood  to  the  heart. 

The  PULMONARY  ARTERY  ascending  from  the  right  ven- 
tricle between  the  two  auricles,  overlies  and  partially  con- 
ceals the  aorta;  at  about  two  inches  from  its  commencement 
it  divides  into  the  right  and  left  pulmonary  arteries;  at  the 
point  of  division  the  remains  of  the  ductus  arteriosus  will 
be  found  as  a  fibrous  cord  extending  from  this  vessel  to  the 
aorta.  The  left  pulmonary  artery  passes  under  the  arch  of 
the  aorta,  and,  emerging  from  the  pericardium,  enters  the 
left  lung  in  front  and  a  little  above  the  left  primary  bron- 
chus. The  right  artery  passes  in  front  of  the  descending 
aorta,  and  enters  the  right  lung  in  front  and  a  little  below 
the  right  primary  bronchus.  These  vessels,  though  carrying 
venous  blood,  are  called  arteries,  because,  like  arteries,  they 
carry  the  blood  away  from  the  heart. 

The  ARCH  OF  THE  AORTA  commences  at  the  anterior  part 
of  the  left  ventricle ;  emerging  between  the  auricles  and 
behind  the  pulmonary  artery,  it  ascends,  turning  gradually 
to  the  left,  and,  passing  through  the  pericardium,  curves 
;Over  the  left  primary  bronchus,  giving  off  the  large  vessels 
for  the  head  and  arms,  which  will  be  studied  in  connection 
with  the  neck  (p.  56);  it  then  passes  downward  into  the 
posterior  mediastinum  to  become  the  descending  aorta. 
The  portion  just  described  is  called  the  arch,  from  the 
curved  direction  which  it  takes,  and  is  divided  into  an 
ascending,  transverse,  and  descending  portion.  The  ascend- 
ing is  the  part  within  the  pericardium ;  the  transverse  that 
from  which  the  great  vessels  originate;  and  the  descending 
that  portion  intervening  between  the  last  of  these  vessels 


HEART.  115 

and  the  lower  border  of  the  third  dorsal  vertebra,  where 
the  thoracic  aorta  begins. 

The  bifurcation  of  the  trachea  is  the  division  of  that  air- 
tube  into  the  right  and  left  primary  bronchi.  These 
divisions  retain  the  structure  of  the  trachea,  and  are  made 
up  of  similar  though  smaller  and  less  perfect  cartilaginous 
rings.  The  right  bronchus  is  about  an  inch  in  length,  and 
enters  the  lung  above  the  right  pulmonary  artery.  The  left 
bronchus  is  about  two  inches  in  length,  and  is  smaller  than 
the  right ;  it  passes  obliquely  downward  under  the  arch  of 
the  aorta,  and  enters  the  lung  below  the  left  pulmonary 
artery.  The  bronchus,  with  the  pulmonary  artery  and  vein, 
constitute  what  is  called  the  root  of  the  lung. 

The  BRONCHIAL  GLANDS,  often  numerous  and  of  large 
size,  frequently  surround  the  bifurcation  of  the  trachea. 
In  the  adult  these  are  sometimes  quite  black  from  carbon- 
aceous deposit,  and  in  scrofulous  subjects  often  contain 
oftened  tuberculous  or  cretaceous  matter. 


HEART. 


The  heart  should  now  be  removed  for  further  examination  by  divid- 
ing its  vessels  at  such  a  point  as  not  to  mutilate  the  auricles.  The 
aorta  must  be  cut  across  near  the  heart. 

The  HEART  is  a  muscular  organ  divided  by  septa  into 
two  halves,  right  and  left ;  each  half  consisting  of  two 
hollow  portions,  an  auricle  and  ventricle,  and  each  ventri- 
cle, conical  in  shape,  being  surmounted  by  its  own  auricle ; 
the  two  ventricles  form  the  bulk  of  the  viscus.  The  auri- 
cles are  quadrangular  in  shape,  with  a  constricted  part  in 
front  called  the  appendix,  and  have  much  thinner  walls 
than  the  ventricles.  The  appendices  auriculae  project  for- 
ward with  their  indented  margins,  the  left  being  the  longest, 
and  nearly  meet  each  other  in  front  of  the  great  vessels. 
Externally  each  cavity  is  defined  by  a  well-marked  furrow 
of  separation,  containing  the  ramifications  of  the  vessels 
destined  to  the  proper  nourishment  of  the  heart;  that 
between  the  auricles  and  ventricles  amounts  almost  to  a 
constriction  of  the  organ.  A  quantity  of  fat  fills  up  the 
sulcus  that  would  otherwise  be  formed. 

The  anterior  surface  of  the  heart  may  be  distinguished 
from  the  posterior  by  the  appendices  of  the  auricle,  which 
meet  in  front  and  not  behind,  and  by  the  pulmonary  artery 
which  lies  in  front  of  the  aorta.  The  left  ventricle  is  the 
thickest  and  forms  the  apex  of  the  viscus,  a  fact  which  is 


116        ANATOMY     OF    UPPER    EXTREMITY,    ETC. 

not  always  apparent  if  the  heart  has  become  flaccid  and 
shapeless. 

Before  opening  the  heart  the  vessels  011  its  surface  are 
to  be  dissected.  They  are  the  two  coronary  arteries  and 
the  coronary  vein. 

The  CORONARY  ARTERIES,  two  in  number,  are  the  first 
branches  of  the  aorta ;  they  emerge  on  the  sides  of  the 
pulmonary  artery,  and  are  named  right  and  left.  The  right 
coronary  appears  on  the  right  side  of  the  pulmonary  artery 
and  winds  round  between  the  right  auricle  and  ventricle  to 
the  posterior  aspect  of  the  heart,  where  it  anastomoses 
with  the  left  coronary  artery,  which  has  followed  a  similar 
course  on  the  left  side.  A  branch  from  the  right  coronary 
descends  posteriorly  in  the  sulcus  between  the  ventricles. 
The  left  coronary  passes  behind  the  pulmonary  artery  to 
emerge  on  the  left  side  of  that  vessel  and  winds  round 
between*  the  left  ventricle  and  auricle  to  the  back  of  the 
heart,  where  it  anastomoses  with  the  right  coronary  artery. 
The  left  coronary  sends  a  branch  downward  to  the  apex  of 
the  heart  in  the  anterior  sulcus  between  the  ventricles. 

The  anterior  said  posterior  cardiac  veins  accompany  these 
arteries  and  terminate  in  the  GREAT  CARDIAC,  or  CORONARY 
VEIN  ;  this  occupies  the  sulcus  between  the  right  auricle 
and  ventricle  posteriorly,  and  winding  round  to  the  front 
terminates  in  a  dilated  ending,  called  the  CORONARY  SINUS  ; 
its  termination  in  the  sinus  is  marked  by  two  valves,  and 
the  sinus  consists  of  the  portion  intervening  between 
these  two  valves  and  the  coronary  valve  where  it  opens 
into  the  right  auricle. 

The  nerves  of  the  heart  are  furnished  by  the  superficial 
cardiac  plexus,  which  surrounds  the  origins  of  the  aorta  and 
pulmonary  artery.  The  deep  cardiac  plexus  lies  between 
the  trachea  and  the  arch  of  the  aorta.  These  plexuses  are 
derived  from  the  sympathetic  and  pneumogastric  nerves, 
and  in  them  terminate  the  cervical  cardiac  branches  (p.  53). 

The  right  auricle  is  opened  by  introducing  the  point  of  the  scissors 
into  the  superior  vena  cava,  and  cutting  toward,  and  nearly  to,  the  in- 
ferior vena  cava ;  from  the  middle  of  this  incision  another  is  made 
to  the  tip  of  the  appendix. 

In  the  RIGHT  AURICLE  the  following  parts  are  to  be 
noticed : — 

The  endocardium  is  the  smooth  transparent  lining  mem- 
brane, common  to  all  the  cavities  of  the  heart,  and  con- 


HEART.  117 

tinuous  with  the  inner  coat  of  the  vessels.  When  it  passes 
from  an  auricle  to  a  ventricle,  or  from  a  ventricle  to  an 
artery,  it  forms  duplicatures,  or  valves,  in  which  fibrous 
tissue  is  inclosed. 

The  Eustachian  valve  is  situated  between  the  lower  cava 
and  the  auriculo-ventricular  opening;  it  is  a  semilunar  fold, 
sometimes  rudimentary  and  sometimes  developed  into  a 
well-formed  valve  with  a  reticulated  margin.  During  foetal 
life  this  structure  serves  to  direct  the  blood  from  the  inferior 
cava  toward  the  foramen  ovale. 

The  coronary  valve  is  occasionally  connected  with  the 
preceding  ;  this  also  is  a  semilunar  fold  stretching  across 
the  orifice  of  the  coronary  sinus,  which  enters  the  auricle 
just  below  the  inferior  vena  cava. 

The  foramina  Thebesii  are  the  apertures  of  minute  veins 
found  in  various  parts  of  the  cavity,  and  which,  coming 
from  the  muscular  structure  of  the  heart,  pour  their  con- 
tents directly  into  the  auricle. 

The  fossa  ovalis  is  a  rounded  depression  situated  on  the 
septum  between  the  auricles,  characterized  by  a  well-defined 
margin,  and  called  the  annulus  ovalis;  it  is  the  remains  of 
the  foramen  ovale  of  fnetal  life.  Not'unfrequently  the  annu- 
lus forms  a  sort  of  valve  upon  one  side  of  the  fossa,  beneath 
which  a  probe  may  be  insinuated  and  passed  into  the  left 
auricle,  the  foramen  remaining  imperfectly  closed;  this  may 
be  consistent  with  an  undisturbed  condition  of  the  circu- 
lation. 

The  musculi  pectinati  are  parallel  muscular  columns, 
symmetrically  arranged,  and  chiefly  confined  to  the  parietes 
of  the  auricular  appendix. 

The  auriculo-ventricular  orifice  consists  of  a  fibrous  ring, 
with  which  are  connected  the  folds  of  membrane  consti- 
tuting the  tricuspid  valve. 

The  right  ventricle  is  opened  by  introducing  one  blade  of  the  scissors 
through  the  auriculo-ventricular  orifice,  and  incising  its  wall  along  the 
outer  edge,  nearly  to  the  apex  of  the  heart ;  from  the  ventricle  pass 
the  scissors  into  the  pulmonary  artery,  and  make  an  incision,  which, 
commencing  at  the  termination  of  the  former,  shall  pass  upward,  par- 
allel to  the  ventricular  septum,  dividing  the  pulmonary  artery.  The 
V-shaped  flap  thus  made,  when  lifted,  will  expose  the  ventricle. 

The  RIGHT  VENTRICLE  is  remarkable  for  its  fleshy  bands 
and  the  generally  irregular  character  of  the  surface  of  its 
cavity ;  near  the  aperture  of  the  pulmonary  artery,  how- 
ever, its  walls  become  comparatively  smooth. 


118        ANATOMY    OF    UPPER    EXTREMITY,    ETC. 

The  columnae  carnese  are  the  muscular  columns,  inter- 
lacing in  all  directions,  which  give  the  ventricle  its  charac- 
teristic appearance. 

The  chordae  tendineae  are  small  tendinous  bands  attached 
to  certain  of  the  columnae  carnese,  and  extending  from  them 
to  the  free  edge  of  the  tricuspid  valve ;  they  interlace  with 
each  other,  and  several  of  them  converge  to  one  column 
for  attachment. 

The  tricuspid  valve  consists  of  three  or  more  folds  of 
the  lining  membrane  of  the  heart,  strengthened  by  fibrous 
tissue,  and  attached  by  their  base  to  the  auriculo-ventricu- 
lar  orifice,  and  by  their  free  edge,  which  is  usually  a  little 
thicker  than  elsewhere,  to  the  chordae  tendineae.  This  valve 
obstructs  the  regurgitation  of  the  blood  from  the  ventricle 
to  the  auricle,  the  chordae  tendineae  preventing  its  flaps  from 
being  pressed  through  into  the  auricle. 

The  infundibulum,  or  conus  arteriosus,  is  that  dilated 
portion  of  the  ventricle  from  which  the  pulmonary  artery 
arises;  it  is,  as  it  were,  separated  from  the  rest  of  the 
ventricle  by  a  sort  of  constriction ;  it  has  fewer  columnae 
carneae  than  other  parts  of  the  cavity. 

The  lining  membrane,  at  the  commencement  of  the  pul- 
monary artery,  forms  three  crescentic  folds,  calle'd  sigmoid, 
or  semilunar  valves.  Attached  by  their  base,  they  are 
free  along  their  concave  margin,  and  look  upward  in  the 
course  of  the  vessel.  The  margin  of  these  valves  is  often 
perforated  by  small  openings,  and  each  valve  contains  in 
the  centre  of  its  concavity  a  little  fibrous  nodule,  called  the 
corpus  Arantii;  this  is  sometimes  directly  at  the  edge,  at 
other  times  a  little  distant  from  it.  Behind  each  of  these 
valves  the  pulmonary  artery  forms  dilatations  like  those 
similarly  placed  in  the  aorta,  but  not  nearly  so  well  marked. 

The  left  auricle  may  be  opened  by  a  transverse  incision  along  its 
ventricular  border. 

N 

The  LEFT  AURICLE  is  smaller  than  the  right,  but  has, 
however,  somewhat  thicker  walls.  It  has  four  openings  for 
the  pulmonary  veins,  two  upon  each  side ;  occasionally,  two 
of  them  coalesce.  The  septum  auriculae  has,  upon  this  side, 
no  trace  of  the  fossa  ovalis,  except  when  an  opening  exists, 
and  then  a  small  valvular  fold  may  be  observed.  The  mus- 
culi  pectinati  are  found  only  in  the  appendix.  The  auriculo- 
ventricular-  orifice  is  smaller  than  that  of  the  right  side. 


HEART.  119 

To  expose  the  left  ventricle,  make  a  short  incision  into  it  with,  a 
knife  close  to  the  septum  ;  pass  the  finger  through  this  into  the  aorta, 
and  upon  it,  as  a  director,  divide  the  ventricle  and  aorta  with  the 
scissors,  keeping  close  to  the  septum,  passing  between  the  two  ap- 
pendices auriculae,  and  holding  aside  the  pulmonary  artery,  so  as  not 
to  injure  that  vessel  in  making  the  section. 

The  LEFT  VENTRICLE  is  more  conical  in  shape  than  the 
right,  and  its  walls  are  twice  as  thick  and  much  more 
muscular;  its  surface  is  irregular  from  the  columnar  carnese, 
but  near  where  the  aorta  arises  the  walls  are  smooth. 

The  mitral  valve  will  have  been  left  undivided  if  the 
ventricle  is  opened  as  has  been  directed.  It  consists  of 
two  folds  of  the  lining  membrane,  attached  to  the  anriculo- 
ventricular  orifice,  and  connected  to  the  columnre  carnea? 
by  chordae  tendinere  in  a  manner  similar  to  that  described 
as  existing  upon  the  right  side.  The  chordae  tendinese 
converge  to  be  inserted  in  two  distinct  bundles  into  the 
columnar  carnese ;  they  are  stronger,  but  less  numerous, 
than  those  of  the  right  ventricle,  and  the  same  may  be  said 
of  the  columnaa  cameae.1 

The  septum  ventriculorum  seems  to  form  part  of  the  left 
rather  than  of  the  right  ventricle,  being  concave  on  its  left 
and  convex  on  its  right  side. 

The  aortic  semilunar  valves  are  found  at  the  commence- 
ment of  the  aorta,  nearly  on  a  level  with  the  mitral  valve. 
They  are  stronger,  though  similar  in  number  and  in  general 
shape  to  those  of  the  pulmonary  artery ;  the  corpora  Arantii 
are  more  developed,  and  the  dilatations  of  the  vessel  behind 
each  segment  are  much  more  pronounced ;  they  are  here 
called  the  aortic  sinuses,  or  sinuses  of  Valsalva. 

The  orifices  marking  the  origin  of  the  anterior  and  pos- 
terior coronary  arteries  will  be  observed  just  behind  the 
semilunar  valves.  Occasionally,  these  arteries  arise  from  a 
common  trunk,  and  their  number  is  sometimes  increased  to 
three.  Their  course  has  been  described  (p.  116). 

The  student  should  at  some  time  avail  himself  of  an  opportunity 
to  examine  the  interior  of  the  heart,  prepared  after  the  following  me- 
thod. Having  washed  out  the  blood  and  fibrin  contained  in  its  cavi- 
ties, they  are  to  be  distended,  by  filling  them  from  a  syringe,  with 
undiluted  alcohol,  and  confining  it  there  by  tying  all  the  vessels  ; 
then  immersing  the  whole  organ  in  a  jar  filled  with  alcohol,  in  a  few 

1  The  letters  L.  M.  (so  familiar  in  another  connection)  will  give  the 
student  a  mnemonic  key  to  the  side  to  which  the  mitral  valve  belongs. 
(L.  M.,  left,  mitral.) 


120        ANATOMY    OF    UPPER    EXTREMITY,   ETC. 

days  it  will  become  so  stiffened  and  hardened  that  it  may  be  opened 
and  the  interior  examined,  by  windows  cut  into  the  cavities,  without 
its  walls  collapsing;  the  valves  will  be  preserved  so  nearly  in  their 
natural  condition  as  to  convey  a  much  clearer  idea  of  their  character 
and  relations  than  can  be  otherwise  obtained. 


DISSECTION  IV. 

POSTERIOR    MEDIASTINUM. 

To  examine  the  posterior  mediastinum,  the  left  lung  should  be  lifted 
from  its  pleural  cavity  and  turned  over  to  the  opposite  side,  where  it 
should  be  confined,  or  held  resting  in  the  space  that  was  occupied  by 
the  heart.  It  may  be  desirable,  in  order  better  to  get  at  the  parts  to 
be  dissected,  to  remove  the  anterior  halves  of  the  ribs  on  one  side  ; 
this  can  be  accomplished  by  the  saw,  or  by  bone  forceps. 

The  POSTERIOR  MEDIASTINUM  is  bounded  in  front  by  the 
posterior  surface  of  the  pericardium,  behind  by  the  verte- 
bral column,  and  on  each  side  by  the  pleura.  It  contains 
the  thoracic  aorta  and  vena  azygos,  the  oesophagus  and 
thoracic  duct,  and  the  pneumogastric  and  sympathetic 
nerves. 

The  continuity  of  the  pleura,  as  it  is  reflected  from  the 
base  of  the  lung  to  the  vertebrae,  ribs,  and  diaphragm,  will 
now  be  well  seen,  and  the  present,  perhaps,  affords  the  best 
opportunity  of  appreciating  the  manner  in  wrhich  one  part 
of  a  serous  membrane  is  attached  to  the  parietes  of  a  cavity, 
and  the  other  to  the  organ  contained  in  it ;  the  organ  being 
in  reality  outside  of  it,  and  merely  pushing  inward  the  part 
covering  it. 

The  left  pleura  is  to  be  carefully  dissected  from  the  subjacent  parts, 
the  whole  length  of  the  thorax.  This  will  expose  the  contents  of  the 
mediastinum. 

The  PNEUMOGASTRIC  NERVES  will  be  found  lying,  the 
left  upon  the  anterior  surface  of  the  oesophagus ;  the  right 
upon  the  posterior  surface.  They  give  off  numerous  fila- 
ments to  the  oesophagus  as  they  descend  upon  it  to  the 
stomach,  where  they  terminate  in  gastric  branches.  They 
also  give  off  pulmonary  and  cardiac  branches,  and  form  a 
large  plexus  behind  the  root  of  the  lung,  with  which  are 
connected  some  filaments  from  the  gangliated  cord  of  the 
sympathetic.  In  the  upper  part  of  the  thorax  they  send  ol 


POSTERIOR    MEDIASTINUM.  121 

the  recurrent  laryngeal  nerves,  which  pass  upward  beside 
the  trachea  to  the  larynx;  upon  the  left  side  this  nerve 
curves  round  the  arch  of  the  aorta ;  on  the  right  it  curves 
round  the  subclavian  artery  (p.  56). 

he  THORACIC  AORTA  commences  at  the  lower  border  of 
third  dorsal  vertebra ;  it  lies  at  first  upon  the  left  side 
of  the  vertebral  column,  and  then  inclines  inward  to  the 
median  line;  as  it  passes  through  the  diaphragm  it  rests 
upon  the  fronts  of  the  vertebrae.  It  gives  off  the  follow- 
ing branches,  viz : — 

Bronchial, 

(Esophageal, 

Intercostal. 

The  bronchial  arteries,  two  or  more  in  number,  and  very  irregular  in 
their  origin,  are  usually  found  on  the  anterior  aspect  of  the  aorta,  just 
as  the  arch  ceases  to  make  its  curve  ;  they  are  of  considerable  size, 
and  pass  immediately  to  the  primary  bronchi,  upon  which  they  ramify 
in  a  tortuous  manner,  giving  small  twigs  to  the  oesophagus  and  peri- 
cardium, and  terminating  in  the  parenchyma  of  the  lungs,  of  which 
they  are  the  nutrient  vessels. 

The  cesofjhageal  arteries  vary  in  number,  and  are  small  branches 
rising  from  the  front  of  the  aorta,  and  distributed  upon  the  oesopha^ 

The  intercostal  arteries,  nine  in  number,  upon  each  side,  are  given 
off  from  the  posterior  aspect  of  the  aorta.  The  right  intercostals  are 
the  longest,  the  position  of  the  aorta  obliging  them  to  arch  over  the 
bodies  of  the  vertebrae.  They  supply  each  intercostal  space  except 
the  two  upper,  which  are  furnished  by  a  branch  from  the  subclavian 
(p.  59).  Each  artery  is  accompanied  by  a  nerve  and  vein,  the  former 
being  the  anterior  branch  of  the  spinal  nerves,  and  the  latter  a  branch 
of  the  vena  azygos.  The  artery  occupies  the  upper  part  of  the  inter- 
costal space,  lying  in  the  groove  of  the  lower  border  of  the  rib,  between 
the  two  layers  formed  by  the  external  and  internal  intercostal  mus- 
cles ;  it  passes  forward  to  inosculate  with  the  anterior  intercostal 
branch  of  the  internal  mammary,  giving  off  at  various  parts  of  its 
course  external  branches,  which  perforate  the  intercostal  space  to  go 
to  the  muscles  and  integument  of  the  back  and  thorax.  From  one  of 
these  branches  in  the  dorsal  region  a  spinal  twig  goes  to  the  interior 
of  the  vertebral  canal. 

The  lungs  should  now  be  removed,  by  dividing  the  trachea  just 
above  its  bifurcation. 

The  (ESOPHAGUS  is  a  hollow  muscular  tube,  extending 
from  the  pharynx  to  the  stomach.  The  cervical  portion  is 
described  at  p.  62.  The  thoracic  portion  enters  the  chest 
on  the  left  of  the  median  line,  passes  beneath  the  arch  of 
the  aorta,  to  continue  on  the  right  side  of  that  trunk  to 
11 


122        ANATOMY    OF    UPPER    EXTREMITY,    ETC. 

the  lower  part  of  the  chest,  where  it  again  inclines  to  the 
left,  over  the  aorta,  and  passes  through  the  oesophageal 
opening  of  the  diaphragm. 

The  O3sophagus  has  a  muscular  and  a  mucous  coat ;  the 
muscular  coat  is  made  up  of  longitudinal  and  circular 
fibres,  and  is  connected  with  the  mucous  by  an  intervening 
layer  of  cellular  tissue  ;  the  mucous  coat  is  of  a  pale  color, 
and  moves  freely  upon  the  muscular,  the  contraction  of 
which  throws  it  into  longitudinal  folds. 

The  SYMPATHETIC  NERVE  consists  of  two  portions.  The 
first  is  the  prevertebral  portion,  made  up  from  the  cardiac 
nerves,  descending  from  the  cervical  ganglia  (p.  53),  the 
branches  of  which,  uniting  with  filaments  from  the  recur- 
rent laryngeal  and  pneumogastric  nerves,  form  the  cardiac 
and  pulmonary  plexuses,  distributed  over  the  origin  of  the 
great  vessels  of  the  heart,  and  to  the  heart  itself,  the  root 
of  the  lungs,  and  the  trachea.  These  can  only  be  satisfac- 
torily studied  by  special  dissections. 

The  second  or  vertebral  portion  of  the  sympathetic,  con- 
sists of  a  chain  of  twelve  connected  ganglia,  situated  near 
the  heads  of  the  ribs,  covered  in  by  the  pleura,  and  continu- 
ous with  those  of  the  neck  and  abdomen.  The  upper  gan- 
glion is  the  largest,  and  the  two  lower  are  anterior  to  the 
line  of  the  others.  Each  ganglion  furnishes  a  branch  to  the 
intercostal  nerves,  and  from  the  upper  six,  small  branches 
are  sent  to  the  aorta  and  mediastinum.  Branches  from 
the  sixth,  seventh,  eighth,  and  ninth,  unite  to  form  the 
great  splanchnic  nerve,  which  passes  through  the  dia- 
phragm, by  the  side  of  its  crus,  to  join  the  semilunar  gan- 
glion. Branches  from  the  tenth  and  eleventh  ganglia  form 
the  lesser  splanchnic  nerve,  which,  piercing  the  diaphragm, 
goes  to  join  the  renal  and  coeliac  plexuses.  A  branch  from 
the  twelfth  ganglion,  occasionally  communicating  with  the 
preceding  nerve,  also  pierces  the  diaphragm,  and  joins  the 
renal  and  coeliac  plexuses,  under  the  name  of  the  third  or 
renal  splanchnic  nerve. 

The  INTERCOSTAL  NERVES,  twelve  upon  each  side,  are  the 
anterior  branches  of  the  spinal  nerves  of  the  dorsal  region. 
They  pass  forward  between  the  two  muscular  layers  of 
the  intercostal  space,  perforating  the  external  muscle  an- 
teriorly, to  be  distributed  to  the  integument  of  the  front  of 
the  thorax.  Each  nerve  receives  a  short  branch  from  the 
ganglionic  trunk  of  the  sympathetic.  The  first  intercostal 
nerve  sends  a  large  branch  to  join  the  brachial  plexus  ;  the 


POSTERIOR    MEDIASTINUM.  123 

second  gives  off  the  intercosto-humeral  branch  (p.  108),  and 
the  twelfth  a  branch  to  the  iirst  lumbar  nerve,  to  assist  in 
forming  the  lumbar  plexus. 

By  removing  a  portion  of  the  oesophagus,  the  az}-gos 
veins  will  be  brought  into  view  ;  they  are  two  in  number, 
and  are  named  major  and  minor. 

The  AZYGOS  MAJOR  VEIN,  commencing  by  branches  com- 
municating with  the  right  lumbar  and  renal  veins,  and 
sometimes  also  with  the  inferior  vena  cava,  passes  through 
the  aortic  opening  of  the  diaphragm,  and  ascends  upon  the 
bodies  of  the  vertebrae  at  the  right  side  of  the  thoracic 
aorta,  receiving  the  right  intercostal  veins  in  its  course. 
Opposite  the  third  intercostal  space  it  arches  forward 
above  the  root  of  the  right  lung,  and  enters  the  superior 
cava,  just  before  that  vessel  penetrates  the  pericardium. 
The  AZYGOS  MINOR  VEIN  commences  on  the  left  side 
>m  the  lumbar,  or  renal  veins,  passes  into  the  thorax  with 
ie  aorta,  or  beneath  the  border  of  the  diaphragm,  ascends 
>n  the  left  side  of  the  vertebral  Column,  and  at  about  the 
>venth  or  eighth  dorsal  vertebra,  crosses  beneath  the  aorta 
id  thoracic  duct,  to  enter  the  vena  azygos  major.  It  re- 
iives  the  lower  intercostal  veins  of  the  left  side.  The 
iperior  intercostal  veins  enter  a  trunk  which  joins  with 
ie  left  vena  innominata,  or  with  the  azygos  minor. 

The  thoracic  duct  is  difficult  to  demonstrate  or  isolate  from  the  sur- 
rounding tissues,  which  it  resembles  in  color ;  by  making  a  snip  with 
the  scissors  into  the  duct,  then  inserting  the  blow-pipe,  and  inflating 
it,  it  will  become  distended,  and  its  course  made  apparent. 

The  THORACIC  DUCT  commences  in  an  enlargement,  to 
which  the  lymphatics  of  the  abdomen  converge,  called  the 
receptaculum  chyli ;  this  lies  beside  the  right  crus  of  the 
diaphragm,  between  the  aorta  and  vena  cava.  The  duct, 
about  the  size  of  a  wheat  straw,  ascends  between  the  aorta 
and  vena  az}'-gos  major,  crosses  the  vertebral  column  at 
the  second  dorsal  vertebra,  and  continuing  upward  along 
the  left  side  of  the  ojsophagus,  enters  the  left  subclavian 
vein  near  its  junction  with  the  internal  jugular.  A  small 
duct,  called  the  ductus  lymphaticus  dexter,  being  the  termi- 
nal duct  of  the  lymphatics  of  the  head,  neck,  and  portions 
of  the  right  side  of  the  upper  part  of  the  bod}-,  enters  the 
right  subclavian  at  its  junction  with  the  right  internal 
jugular  vein  (p.  55).  The  thoracic  duct  is  sometimes 
double,  either  in  the  whole  or  part  of  its  course.  It  oc- 


124        ANATOMY    OF     UPPER    EXTREMITY,    ETC 

casionally  empties  into  the  vena  azygos  major,  that  being 
its  normal  destination  in  some  mammalia.  The  duct  has 
been  found  also  on  the  left  side  of  the  aorta. 

The  intercostal  spaces  are  filled  by  two  muscular  layers 
called  external  and  internal  intercostal  muscles. 

The  EXTERNAL  INTERCOSTAL  MUSCLES  are  eleven  in  mini 
ber  on  each  side ;  they  arise  from  the  outer  lip  of  the  lowe 
border  of  the  rib,  and  are  inserted  into  the  correspondin 
part  of  the  rib  next  below ;    the  fibres  run  forward  and 
downward,  and  extend  from  the  tubercle  of  each  rib  nearly 
to  its  cartilage. 

The  INTERNAL  INTERCOSTAL  MUSCLES,  also  eleven  in 
number  on  each  side,  arise  from  the  inner  lip  of  the  lower 
border  of  the  rib,  and  are  inserted  into  the  upper  border 
of  the  rib  next  below ;  they  extend  from  the  sternum  to 
the  angles  of  the  ribs,  and  their  fibres  are  directed  back- 
ward and  downward.  The  internal  muscular  layer  is 
covered  by  the  pleura,  and  the  intercostal  vessels  and 
nerves  ramify  between  the  two  muscles. 

The  INFRA-COSTALES  MUSCLES  are  bundles  of  muscular 
fibres  on  the  inner  surface  of  the  ribs,  having  the  same 
direction  as  the  internal  intercostals :  they  stretch  across 
two  or  three  spaces,  and  vary  in  size  and  number.  They 
are  most  constant  on  the  lower  ribs. 

LUNGS. 

Dissecting-room  subjects  rarely  afford  a  good  opportu- 
nity for  the  examination  of  the  lungs  ;  riddled  with  tuber- 
cular cavities,  bound  down  by  old  pleuritic  adhesions,  they 
are  apt  to  be  mutilated  in  their  removal,  or  rendered 
puzzling  to  the  student,  by  their  unnatural  condition. 

If  uninjured,  the  lungs  should  be  inflated  for  their  examination. 

The  LUNG  is  conical  in  shape,  and  presents  a  rounded 
apex  which  extends  above  the  first  rib,  and  a  concave  base, 
or  diaphragmatic  surface,  the  concavity  being  greatest  in 
the  right  lung,  owing  to  the  position  of  the  liver;  the  sharp 
border  of  this  surface  penetrating  the  space  between  the 
diaphragm  and  ribs  posteriorly,  makes  the  posterior  longi- 
tudinal measurement  of  the  lung  greater  than  the  anterior. 
The  sides  of  the  lung,  with  the  exception  of  the  medias- 
tinal,  present  a  smooth  convex  surface,  covered  with 
the  pleura,  and  conforming  to  the  shape  of  the  thoracic 
cavity.  The  mediastinal  surface  is  concave,  the  position 


i 


BACK    AND    POSTERIOR    CERVICAL    REGION.      125 

of  the  heart  making  the  concavity  of  the  left  lung  the 
greatest.  The  anterior  border  is  sharp,  and  the  posterior 
rounded.  Each  lung  is  divided  into  an  upper  and  lower 
lobe  by  a  deep  fissure,  the  upper  lobe  of  the  right  side 
being  subdivided  by  a  more  shallow  fissure,  thus  making 
a  third,  or  middle  lobe.  The  lobes  are  sometimes  multi- 
plied, and  offer  great  variety  in  shape.  The  lungs  vary  in 
color,  according  to  age,  or  their  more  or  less  healthy  state  ; 
usually,  they  are  of  a  grayish  tint,  mottled  with  blackish 
spots.  The  sitrface  is  figured  with  irregular  polygonal 
outlines,  indicating  the  lobules  of  which  they  are  made 
up,  and  these  lobules  are  subdivided  by  still  smaller  lines 
which  are  the  walls  of  the  cells  that  compose  them ;  the 
lobules  are  best  seen  in  infant's  lungs,  or  in  those  of  very 
young  persons.  When  cut  into,  the  lungs  are  found  to  be 
of  a  spongy  texture,  and  if  in  a  natural  state,  upon  pres- 
sure, the  air  may  be  felt  escaping  in  fine  bubbles  from  the 
air-cells,  giving  the  sensation  called  crepitation. 

The  lung  is  made  up  of  the  various  structures  which  enter 
it  at  its  root.  The  bronchi  may  be  traced  by  a  director  and 
scissors,  dividing  into  principal  trunks  for  each  lobe,  and 
then  subdividing,  until  lost  by  their  extreme  tenuity  ;  the 
cartilaginous  rings  which  were  found  at  their  commence- 
ment, becoming  less  and  less  apparent. 

At  the  divided  root  of  the  lungs,  the  bronchus  is  poste- 
rior, and  the  pulmonary  veins  anterior,  the  pulmonary 
artery  being  between  the  two.  In  the  direction  from  above 
downward,  the  position  on  the  right  side  is — bronchus,  pul- 
monary artery,  and  pulmonary  veins ;  but,  on  the  left  side, 
it  is  changed  to  the  order — artery,  bronchus,  and  veins. 


DISSECTION  V. 

THE    BACK   AND   POSTERIOR   CERVICAL   REGION. 

The  dissection  of  the  back  comes  next  in  order,  but  if  the  other 
members  of  the  class  are  not  ready  to  turn  the  subject  over,  the  dis- 
section of  the  arm  may  be  resumed,  the  description  of  which  will  be 
found  in  Dissection  VII. 

The  subject  must  be  turned  upon  its  face,  and  rest  upon  blocks  as 
before  ;  the  head  should  hang  over  the  end  of  the  table,  and  the  arms 
over  its  sides  ;  by  so  doing,  the  muscles  will  be  put  upon  the  stretch. 
A  longitudinal  incision  is  to  be  made  along  the  median  line,  from  the 

11* 


12G        ANATOMY     OF    UPPER    EXTREMITY,   ETC. 

occiput  to  the  sacrum,  and  another  from  just  below  the  middle  of  the 
dorsal  vertebras  to  the  acromion  of  the  scapula;  the  flaps,  thus  formed, 
are  to  be  raised  and  reflected. 

The  muscles  of  the  back,  always  difficult  to  dissect  neatly,  are  often 
made  more  so,  by  the  intiltration  of  fluids  which  have  gravitated  to  this 
part  of  the  body,  while  it  remained  dependent.  The  subcutaneous 
cellular  tissue  is  sometimes  so  much  thickened  by  this  infiltration, 
that  it  is  difficult  to  tell  when  the  plane  of  the  muscles  is  reached. 
If  this  condition  of  things  exist,  care  must  be  taken  not  to  go  through 
the  thin  aponeurotic  tendons  by  a  too  hasty  incision. 

The  dissection  of  the  back  is  usually  made  for  the  benefit  of  the 
class  in  common  (with  the  exception  of  the  cervical  region,  which 
belongs  more  properly  to  the  head),  and  is  generally  accomplished  by 
two  of  the  class,  the  others  assisting  by  reading  the  description  of  the 
parts  successively  dissected.  The  student  must  be  prepared  to  find 
a  great  want  of  conformity  between  the  muscles,  as  he  finds  them, 
and  the  precise  description  of  their  origins  and  insertions  as  given  in 
books,  for  they  have  little  of  the  distinct  arrangement  elsewhere  to  be 
found.  Of  many,  the  fibres  are  so  short,  or  so  incompletely  separated, 
that  their  isolation  is  extremely  difficult.  "The  deeper  ones,"  says 
John  Bell,  "  might  fairly  be  reckoned  as  one  muscle,  since  they  are 
one  in  place  and  in  office,  but  which  the  anatomist  may  separate  into 
an  infinite  number,  with  various  and  perplexing  names,  an  opportu- 
nity which  anatomists  have  been  careful  not  to  lose." 

The  trapezius  and  the  latissimus  dorsi  muscles  form  th 
superficial  layer,  and  together  cover  the  whole  region  oJ 
the  back. 

The  TRAPEZIUS  MUSCLE  arises  by  a  thin  aponeurotic  ten- 
don (easily  divided  and  injured  if  much  care  is  not  taken), 
from  the  occipital  protuberance  and  adjacent  part  of  the 
superior  curved  line  of  the  occipital  bone,  from  the  ligt 
mentum  nuchse,  and  from  the  spinous  processes,  and  supra- 
spinous  ligament  of  the  last  cervical  vertebra,  and  of 
variable  number  (six  to  twelve)  of  those  of  the  dorsal  re- 
gion ;  from  this  extended  origin  the  fibres  converge,  so  as 
to  give  the  muscle  a  triangular  shape,  and  are  inserted  int< 
the  outer  third  of  the  clavicle,  the  acromion  process,  am 
the   spine   of  the   scapula.      The   spinal   accessory   nerve 
pierces  the  anterior  border  of  this  muscle  and  is  distributed 
to  its  fibres. 

The  LIGAMENTUM  NUCH^E  is  a  strong  layer  of  elastic 
fibrous  tissue,  extending  from  the  spine  of  the  occiput  to 
that  of  the  seventh  cervical  vertebra ;  it  is  a  rudimentary 
development  of  the  elastic  band  which  serves  to  sustain 
the  weight  of  the  head  in  the  Ruminantia. 

The  LATISSIMUS  DORSI  MUSCLE  arises  from  the  spiuous 


BACK    AND    POSTERIOR    CERVICAL    REGION.      127 

processes,  and  supra-spinous  ligament  of  from  four  to  eight 
of  the  dorsal,  those  of  all  the  lumbar,  and  two  of  the  sacral 
vertebrae,  from  the  posterior  third  of  the  crest  of  the  ilium, 
and  from  three  or  four  of  the  lower  ribs,  by  serrations  which 
indigitate  with  similar  processes  of  the  external  oblique 
muscle  of  the  abdomen;  the  fibres  pass  upward  and  for- 
ward to  be  inserted  by  a  strong  flat  tendon  into  the  floor 
of  the  bicipital  groove  of  the  humerus.  In  their  course 
upward  they  overlap  the  inferior  angle  of  the  scapula,  and 
beneath  them,  at  this  point,  a  synovial  bursa  may  some- 
times be  found.  A  distinct  fleshy  slip  is  sometimes  given 
off  from  the  lower  angle  of  the  scapula,  and  a  muscular 
band  often  stretches  across  the  axilla  to  terminate  in  either 
the  pectoralis  major  or  the  coraco-brachialis  muscle. 

Cutaneous  nerves,  branches  of  the  posterior  divisions  of 
the  spinal  nerves,  will  be  observed  perforating  the  spinal 
tendons  of  both  the  last-described  muscles. 

A  triangular  space  will  sometimes  be  found  intervening 
between  the  latissimus  dorsi  and  external  oblique,  only 
remarkable  as  having  been  erroneously  supposed  to  be  a 
point  at  which  intestinal  hernia  was  liable  to  occur. 

The  latissimus  dorsi  is  covered  in  its  dorsal  region  by 
the  trapezius  muscle  and,  at  its  lower  part,  by  a  layer  of  the 
fascia  lumborum ;  this  fascia  consists  of  three  layers;  the 
superficial,  lying  upon  the  latissimus  and  blending  with 
its  aponeurosis  is  attached  to  the  two  lower  ribs,  and  the 
spines  of  the  lumbar  vertebrae ;  the  middle  passes  beneath 
the  latissimns,  between  the  erector  spinae  and  quadratus 
Inmborum,  and  is  attached  to  the  tips  of  the  lumbar  trans- 
verse processes ;  the  internal  passes  in  front  of  the  quadratus 
lumborum,  and  is  attached  to  the  bases  of  the  lumbar  trans- 
verse processes.  These  three  Ia37ers  constitute  the  posterior 
origin  of  the  transversalis  abdominis  muscle. 

The  trapezius  and  latissimus  are  now  to  be  divided  through  the 
middle  of  their  muscular  portions  and  reflected.  In  doing  this,  care 
must  be  taken  not  to  push  too  far  the  separation  between  them  and 
the  muscles  beneath  at  their  spinal  attachments,  inasmuch  as  their 
tendons  are  united  and  confounded  with  those  of  the  next  layer.  In 
removing  the  trapezius,  branches  of  the  supra-scapular  artery  will  be 
divided. 

The  RHOMBOIDEUS  MINOR  MUSCLE  is  a  narrow  band 
arising  from  the  spinous  processes,  and  supra-spinous  liga- 
ment of  the  last  cervical  and  first  dorsal  vertebrae,  and  in- 


128       ANATOMY    OF    UPPER    EXTREMITY,    ETC. 

serted  into  that  part  of  the  border  of  the  scapula  opposit 
the  triangular  space  by  which  its  spine  commences. 

The  RHOMBOIDEUS  MAJOR  MUSCLE,  double  the  width  oi 
the  preceding,  arises  from  the  spinous  processes  and  from 
the  supra-spinous  ligament  of  the  upper  four  or  five  dorsal 
vertebrae,  and  is  inserted  into  the  posterior  border  of  the 
scapula,  below  the  spine  ;  it  is  separated  from  the  rhom- 
boideus  minor  by  a  slight  cellular  interspace. 

These  two  muscles  must  be  carefully  removed,  in  order  to  expose 
those  next  to  be  described  ;  in  so  doing  twigs  of  the  postei'ior  scapu- 
lar artery  will  be  found  distributed  to  them,  and  that  artery  must  be 
respected,  as  it  passes  along  the  posterior  border  of  the  scapula. 

The  SERRATUS  POSTICUS  SUPERIOR  is  a  thin  muscular 
plane,  arising  from  the  spinous  processes  of  one  or  two  of 
the  last  cervical  and  two  or  three  of  the  upper  dorsal  ver- 
tebrae ;  it  passes  downward  and  outward,  and  is  inserted 
by  fleshy  serrations  into  the  upper  borders  of  the  second, 
third,  and  fourth  ribs. 

The  SERRATUS  POSTICUS  INFERIOR,  the  tendon  of  which 
is  inseparably  connected  with  the  aponeurosis  of  the  latissi- 
mus  dorsi  and  the  fascia  lumborum,  arises  from  the  spinous 
processes  of  the  last  two  dorsal  and  first  two  or  three  lum- 
bar vertebrae,  and  passing  obliquely  upward,  is  inserted  by 
fleshy  serrations  into  the  last  four  ribs,  each  successive 
process  extending  further  outward  than  the  one  below. 

A  thin  aponeurotic  lamina,  called  the  vertebral  aponeuro- 
sis extends  between  these  two  last-described  muscles,  bind- 
ing down  the  deeper  muscles,  and  separating  them  from  the 
more  superficial  ones. 

By  dividing  the  serratus  posticus  superior  and  the  subjacent  ver- 
tebral aponeurosis  the  splenius  muscle  will  be  exposed. 

THE  SPLENIUS  MUSCLE,  single  in  its  origin,  divides  into 
a  cervical  and  cranial  part,  known  respectively  as  splenius 
capitis  and  splenius  colli.  It  arises  from  the  spinous  pro- 
cesses and  inter-spinous  ligaments  of  the  last  two  cervical 
and  four  or  five  upper  dorsal  vertebrae,  and,  separating  into 
its  two  divisions,  the  sinenius  capitis  is  inserted  into  the 
space  between  the  two  curved  lines  of  the  occipital  bone 
and  into  the  mastoid  process  of  the  temporal  bone,  where 
it  is  overlapped  by  part  of  the  sterno-mastoid  muscle ;  the 
splenius  colli  is  inserted  into  the  posterior  tubercles  of  the 
transverse  processes  of  three  or  four  of  the  upper  cervical 
vertebrae. 


BACK    AND    POSTERIOR    CERVICAL    REGION.       129 

The  splenii  muscles  of  the  two  sides  do  not  meet  along 
the  median  line,  but  leave  a  space  between  them  filled  with 
dense  areolar  tissue,  the  removal  of  which  displays  the 
complexus  muscle  beneath. 

By  dividing  the  splenius  muscle  the  whole  of  the  levator  anguli 
scapulae  will  be  exposed. 

The  LEVATOR  ANGULI  SCAPULAE  arises  by  distinct  slips 
from  the  posterior  tubercles  of  from  three  to  five  of  the 
superior  cervical  vertebrae,  between  the  insertions  of  the 
scalenus  posticus  and  splenius  muscles,  which  latter,  with 
the  stern o-mastoid  muscle,  overlap  a  portion  of  it,  and  is 
inserted  by  a  fleshy  tendon  into  the  superior  angle  of  the 
scapula.  It  is  sometimes  split  into  several  distinct  mus- 
cles, the  divisions  of  its  origin  continuing  down  to  its 
insertion. 

The  OMO-HYOID  MUSCLE,  connecting  the  scapula  and 
hyoid  bone,  consists  of  two  bellies,  an  anterior  and  a 
posterior.  The  anterior  is  described  at  p.  40.  The  pos- 
terior belly  is  now  seen.  This  portion  arises  from  the 
upper  border  of  the  scapula,  near  the  supra-scapular 
notch,  and  from  the  ligament  which  converts  that  notch 
into  a  foramen ;  it  is  thin  and  ribbon-like,  and  terminates 
beneath  the  sterno-mastoid  muscle  in  a  tendon  which 
separates  the  muscle  into  its  two  halves,  and  which  plays 
through  a  loop  formed  by  the  deep  cervical  fascia.  This 
loop  holds  down  the  tendon  so  that  the  portion  of  the 
muscle  just  described  forms  an  obtuse  angle  with  that  part 
inserted  into  the  os  hyoides. 

The  supra-scapular  nerve  (p.  103)  passes  through  the 
supra-scapular  notch  beneath  this  muscle.  The  supra- 
scapular  artery  (p.  58)  also  passes  beneath  this  muscle,  to 
the  supra-spinous  fossa.  The  posterior  scapular  artery 
(p.  59)  passes  under  the  levator  anguli  scapulae,  and  turns 
downward  along  the  base  of  the  scapula,  beneath  the 
rhomboid  muscles,  to  supply  the  two  surfaces  of  that 
bone. 

In  the  interstices  of  the  muscles  which  remain,  and  in 
those  which  are  to  be  made  in  separating  them  from  each 
other,  numerous  small  arteries  will  be  seen ;  in  the  lumbar 
region,  they  are  posterior  branches  from  the  lumbar  arteries ; 
in  the  dorsal  region,  posterior  branches  from  the  intercostal 
arteries  ;  and  in  the  neck,  posterior  branches  from  the  verte- 
bral arteries,  and  from  the  profunda  cervwis  and  super- 


130        ANATOMY    OF    UPPER    EXTREMITY,    ETC. 

ficialis  cervicis,  offsets  from  the  subclavian  artery.  The 
occipital  artery,  a  branch  of  the  external  carotid  (p.  45), 
will  also  be  seen  emerging  from  beneath  the  tendons  of  the 
sterno-mastoid,  trachelo-mastoid,  and  splenius  muscles,  to 
ramify  upon  the  occipital  bone;  this  artery  sends  off  a 
branch  called  the  princeps  cervicis,  which  passes  down- 
ward between  the  complexus  and  semi-spinalis  colli  mus- 
cles, to  inosculate  with  the  profunda  cervicis. 

The  posterior  branches  of  the  sacral,  lumbar,  dorsal,  and 
cervical  nerves,  will  also  be  observed ;  they  are  mostly 
small  filaments  accompanying  the  arteries,  and  supplying 
the  muscles  and  skin.  The  posterior  branches  of  the  first, 
second,  and  third  cervical  nerves  are  however  larger  than 
the  others,  and  form  a  plexus  upon  the  muscles  of  the 
sub-occipital  region,  called  the  posterior  cervical  plexus. 
The  occipitalis  major  nerve,  from  the  second  cervical,  is  a 
branch  of  considerable  size,  which  passes  upward,  in  com- 
pany with  the  occipital  artery,  and  ramifies  between  the 
integument,  which  it  supplies,  and  the  posterior  belly  of 
the  occipito-frontalis  muscle ;  it  sends  numerous  branches 
to  the  muscles  of  the  back  of  the  neck. 

Under  the  title  of  ERECTOR  SPIN^J  are  included  a  num- 
ber of  muscles  of  different  length,  extending  from  the 
sacrum  to  the  upper  part  of  the  neck ;  small  and  pointed 
over  the  sacrum,  in  the  lumbar  region  the  erector  consti- 
tutes a  single,  inseparable  mass ;  in  thf  dorsal  region  its 
bulk  gradually  lessens,  and  in  the  neck  it  consists  only  of 
slender  prolongations.  A  strong  and  lustrous  tendinous 
expansion  covers  the  sacral  and  lumbar  portion  ;  and  from 
this,  from  the  posterior  surface  of  the  sacrum,  and  from 
the  whole  length  of  each  transverse  process  of  the  lumbar 
vertebrae,  and  the  layer  of  the  fascia  lumborum  external  to 
these,  the  erector  spinse  takes  its  origin.  At  the  level  of 
the  last  rib,  the  muscle  begins  to  separate  into  two  por- 
tions, the  external  being  called  the  sacro-lumbalis,  and  the 
internal  the  longissimus  dorsi. 

The  sacro-lumbalis  muscle  is  inserted  by  separate  tendons  into  the 
angles  of  the  six  lower  ribs ;  here  the  muscle  is  reinforced  by  mus- 
cular fasciculi  arising  from  the  upper  margin  of  all  the  ribs,  inter- 
nally to  th«  preceding  insertions,  and  through  them  the  sacro-luuibalis 
is  continued  to  the  higher  ribs,  and  to  the  transverse  processes  of  three 
or  four  lower  cervical  vertebrae.  There  is  no  separation  between  these 
accessory  fasciculi  and  the  bulk  of  the  sacro-lumbalis  ;  but  those 
derived  from  the  six  or  eight  lower  ribs  and  inserted  into  the  upper 
ribs,  are  often  described  separately,  as  the  musculus  accessories  ad 


BACK    AND    POSTERIOR    CERVICAL    REGION.      131 

sacro-lumbalem ;  and  those  from  the  four  or  five  upper  ribs  which  are 
inserted  into  the  cervical  transverse  processes,  as  the  cervicalis  ascend- 
ens  muscle. 

The  longissimus  dorsi  muscle  is  inserted  into  the  transverse  pro- 
cesses of  all  the  dorsal  vertebrae,  and  to  that  portion  of  from  seven  to 
eleven  ribs,  which  is  situated  wtihin  their  angles  ; — it  is  continued 
upward  into  the  neck  by  a  slender  accessory  portion,  often  described 
as  a  distinct  muscle,  under  the  name  of  the  transversalis  colli,  and 
which,  arising  from  the  tips  of  the  transverse  processes  of  the  four  upper 
dorsal  and  the  seventh  cervical  vertebrae,  is  inserted  into  the  transverse 
processes  of  about  four  cervical  vertebrae,  above  the  preceding,  blend- 
ing with  the  cervicalis  ascendens  and  trachelo-mastoid  muscles. 

The  trachelo-mastoid  muscle  is  the  continuation  of  the  longissimus 
dorsi  to  the  head.  It  arises  from  the  articular  processes  of  three  or 
four  lower  cervical  vertebrae,  on  the  inner  side  of,  and  inseparable 
from,  the  transversalis  colli,  and  is  inserted  into  the  posterior  part  of 
the  mastoid  process,  beneath  the  splenius  and  sterno-mastoid  muscles. 

The  spinal  is  dorsi  is  often  described  as  a  part  of  the  longissimus 
dorsi,  and  it  can  only  be  artificially  separated  from  it.  It  arises  by 
separate  tendons  from  the  spinous  processes  of  the  first  two  lumbar 
nd  last  dorsal  vertebrae,  and  is  inserted  into  from  four  to  eight  of 
spiuous  processes  of  the  upper  dorsal  vertebrae.  The  muscles  of 

e  two  sides  form  a  long  ellipse. 


aon 

sep 

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;: 

an 


The  COMPLEXUS  MUSCLE,  with  the  splenius,  forms  the 
Ik  of  the  back  of  the  neck.  It  arises  from  the  transverse 
•ocesses  of  four  upper  dorsal,  and  from  the  transverse  and 
articular  processes  of  four  lower  cervical  vertebrae,  and  is 
inserted  into  the  occipital  bone  between  the  curved  lines. 
Upon  its  inner  border,  a  large  fasciculus,  consisting  of  two 
bellies  with  an  intervening  tendon,  from  which  peculiarity 
it  has  been  named  biventer  cervicix,  separates  itself  from 
the  principal  mass  of  the  complexus.  . 

The  occipitalis  major  nerve  is  transmitted  to  the  surface 
through  the  complexus  and  trapezius  muscles,  near  their 
cranial  attachment.  As  soon  as  the  nerve  is  free  from  the 
muscles,  it  receives  a  cutaneous  offset  from  the  third  cervi- 
cal nerve.  The  occipital  artery  rests  upon  the  upper  end 
of  the  complexus,  and  beneath  it  the  branch  of  that  artery 
called  the  princeps  cervicis  anastomoses  with  the  profunda 
cervicis. 

The  posterior  belly  of  the  occipito-frontalis  muscle  (p.  15) 
will  be  seen  during  this  dissection.  It  is  a  thin,  flat  plane 
of  muscular  fibres  arising  from  the  outer  part  of  the  supe- 
rior curved  line  of  the  occipital  bone,  and  inserted  into  the 
epicranial  aponeurosis,  by  which  it  is  connected  with  its 
frontal  portion. 


132        ANATOMY    OF    UPPER    EXTREMITY,    ETC.. 

The  erector  spinse,  with  its  accessories  and  the  complexus.  are  now 
to  be  removed  by  dividing  transversely  the  tendon  of  the  former,  close 
to  the  sacrum,  raising  it  from  the  inner  side  and  turning  it  outward. 
The  muscles  which  remain  to  be  examined,  with  the  exception  of  the 
sub-occipital  group,  will  be  left  in  a  very  ragged  condition,  and  ob- 
scured by  the  remains  of  the  numerous  tendons  and  fasciculi  divided 
in  the  removal  of  the  dissected  muscles.  It  is  difficult  to  make  a  neat 
preparation  of  them. 

The  SEMI-SPINALIS  MUSCLE  consists  of  a  thin  and  narrow 
stratum  of  short  muscular  bellies  with  longer  tendons, 
which  stretches  from  the  second  cervical  vertebra  to  the 
lower  part  of  the  dorsal  region ;  each  bundle,  arising  from 
a  transverse  process,  is  inserted  into  a  spinous  process,  the 
fibres  being  directed  downward  and  outward.  The  upper 
bundles  are  larger  than  the  lower,  and  the  number  of  them 
varies  in  different  subjects.  Although  continuous,  the 
upper  four  of  these  muscular  bundles,  those  arising  from 
the  transverse  processes  of  the  four  upper  dorsal  and  in- 
serted into  the  spinous  processes  of  the  four  upper  cervical 
vertebrae,  have  been  named  the  semi-spinalis  colli, — and 
the  lower  six,  those  arising  from  the  transverse  processes 
of  the  six  lower  dorsal  and  inserted  into  the  spinous  pro- 
cesses of  the  four  upper  dorsal  and  two  lower  cervical  ver- 
tebr;e,  the  semi-spinalis  dor  si. 

The  MULTIFLDUS  SPINSE  lies  to  the  inner  side  of  and  be- 
neath the  last-named  muscles,  and  they  must  be  removed 
in  order  to  see  it  in  its  full  extent.  It  reaches  from  the 
sacrum  to  the  axis,  and  consists  of  a  series  of  muscular 
slips,  filling  the  vertebral  groove  at  the  side  of  the  spinous 
processes.  Each  fasciculus  arises  from  a  transverse  pro- 
cess, and  is  inserted  into  the  spinous  process  of  the  first 
or  second  vertebra  above  ;  the  first  slip  arises  from  the 
transverse  process  of  the  third  cervical  vertebra,  and  is 
inserted  into  the  spinous  process  of  the  axis ;  the  last  slip 
arises  from  the  back  of  the  sacrum,  and  is  inserted  into  the 
spine  of  the  fifth  lumbar  vertebra. 

The  LEVATORES  COSTARUM  are  sometimes  considered  as 
accessories  of  the  external  intercostal  muscles  ;  triangular 
in  shape,  they  arise  from  the  transverse  processes  of  the 
dorsal  vertebrae,  and  are  inserted  between  the  tubercle  and 
the  angle  of  the  rib  below.  The  inferior  levatores  some- 
times pass  over  one  rib,  to  be  attached  to  the  second  below 
them.  There  are  twelve  of  these  muscles  on  each  side. 

Between  the  spinous  processes  of  the  cervical  and  lum- 
bar regions  may  be  found  a  series  of  small  muscles  called 


BACK    AND    POSTERIOR    CERVICAL    REGION.      133 

INTER-SPINALES.  In  the  neck,  where  the  spines  are  bifid, 
they  are  arranged  in  pairs ;  they  are  wanting  between  the 
first  two  cervical  vertebrae,  and  in  the  dorsal  region  they 
are  rudimentary  ;  as  their  name  indicates,  their  origin  is 
from  one  spinoiis  process,  and  their  insertion  is  into  that  of 
the  next  vertebra  below  it. 

Similarly  disposed  to  these  last  are  the  INTER-TRANS- 
VERSALES  MUSCLES,  best  marked  in  the  cervical  region, 
where  they  are  arranged  in  pairs,  corresponding  to  the 
anterior  and  posterior  tubercles  of  the  transverse  processes 
between  which  they  are  arranged  ;  the  posterior  muscle  in 
the  upper  inter-transverse  space  is  often  wanting.  The 
posterior  branches  of  the  spinal  nerves  emerge  between  the 
inter-transversales  muscles. 

A  better  defined  series  of  muscles  remains  to  be  ex- 
amined; they  are  those  which  communicate  to  the  head 
its  peculiar  movements ;  they  are  covered  in  by  an  apo- 
neurosis  of  fibrous  tissue,  which  is  to  be  removed ;  in  so 
doing,  the  sub-occipital,  or  first  cervical  nerve,  is  to  be  re- 
spected. 

The  RECTUS  CAPITIS  POSTICUS  MAJOR  arises  from  the 
spine  of  the  axis,  and  spreading,  fan-like,  is  inserted  into 
and  beneath  the  inferior  curved  line  of  the  occipital  bone. 
It  diverges  from  its  fellow  so  as  to  leave  a  deep  interspace 
between  them. 

The  RECTUS  CAPITIS  POSTICUS  MINOR  is  placed  internally 
to  the  preceding;  it  arises  from  the  posterior  border  of 
the  atlas,  and  is  inserted  into  the  occipital  bone  between 
tlie  inferior  curved  line  and  the  foramen  magnum. 

The  OBLIQUUS  INFERIOR  arises  from  the  spinous  process 
of  the  axis,  externally  to  the  rectus  major  muscle,  and  is 
inserted  into  the  transverse  process  of  the  atlas. 

The  OBLIQUUS  SUPERIOR  arises  from  the  transverse  pro- 
cess of  the  atlas,  passes  upward  and  forward,  and  is 
inserted  just  behind  the  mastoid  process,  between  the 
curved  lines  of  the  occipital  bone. 

The  SUB-OCCIPITAL  NERVE,  the  posterior  division  of  the 
first  cervical  nerve,  pierces  the  ligament  between  the  first 
cervical  vertebra  and  the  occipital  bone,  and  appears  in 
the  interval  between  the  recti  and  obliqui  muscles ;  it  is 
distributed  to  these  muscles,  and  sends  a  branch  downward 
to  communicate  with  the  second  cervical  nerve. 

The  strikingly  symmetrical  arrangement  of  the  occipital 
group  of  muscles   cannot   but   be  noticed.     The  muscles 
12 


134        ANATOMY    OF    UPPER    EXTREMITY,   ETC. 

parting  from  the  spine  of  the  axis  form  a  star  with  si: 
points ;  the  inferior  points  being  formed  by  the  semi-spi 
nales  colli,  the  lateral  by  the  obliqui  inferiores,  and  th< 
superior  by  the  recti  capitis  majores. 

SPINAL   CORD   AND    MEMBRANES. 

The  muscles  are  to  be  dissected  away  from  the  sides  of  the  verte- 
bral spines.  With  the  chisel  and  saw  their  arches  are  to  be  divided 
upon  each  side  close  to  the  articular  processes  ;  the  hones  can  only 
be  removed  piecemeal  Mnd  with  difficulty.  This  done,  the  membranes 
of  the  spinal  cord  will  be  exposed. 

The  membranes  of  the  spinal  cord  are  covered  exter- 
nally by  veins  and  by  a  loose  areolar  tissue  containing 
fat  and,  especially  at  the  lower  part,  a  little  fluid ;  they  are 
a  continuation  of  those  of  the  brain,  and,  like  them,  con- 
sist of  dura  mater,  arachnoid,  and  pia  mater. 

The  DURA  MATER  envelops  the  cord  loosely,  and  sends 
tubular  prolongations  along  the  spinal  nerves  issuing  at 
the  intervertebral  foramina;  at  its  lower  part  these  pro- 
longations become  longer  and  lie  for  some  distance  within 
the  spinal  canal.  The  dura  mater  terminates  in  an  imper- 
vious fibrous  process,  which  blends  with  the  periosteum 
covering  the  back  of  the  coccyx. 

The  dura  mater  is  to  be  opened  lengthwise  with  the  scissors  ;  this 
•will  expose  the  arachnoid. 

The  ARACHNOID  is  a  serous  membrane  enveloping  the 
spinal  cord,  and  reflected  upon  the  internal  surface  of  the 
dura  mater.  That  portion  attached  to  the  dura  mater  is 
closely  adherent  to  it,  while  that  in  relation  to  the  cord  is 
loose ;  the  interval  between  the  cord  and  membrane  con- 
stitutes the  sub-arachnoid  space,  and  is  filled  by  a  fluid, 
called  the  cerebro-spinal  (p.  80).  The  arachnoid  envelops 
each  spinal  nerve  and  the  collection  of  nerves  which  ter- 
minates the  cord. 

The  loose  arachnoid  is  to  be  removed  and  the  pia  mater  will  then 
be  exposed. 

The  PIA  MATER  is  a  thin  and  stout  membrane  closely 
investing  the  spinal  cord;  it  forms  a  sheath  for  the  spinal 
nerves  and  inferiorly  is  prolonged  downward  in  a  slender 
process  called  the  filum  terminals,  which  blends  with  the 
terminal  prolongation  of  the  dura  mater. 

On  each  side  of  the  spinal  cord,  extending  its  whole 


SPINAL    CORD    AND    MEMBRANES.  135 

length,  and  separating  the  anterior  and  posterior  roots  of 
the  spinal  nerves,  is  a  white  fibrous  band,  connected  inter- 
nally with  the  pia  mater,  and  having  about  twenty  serra- 
tions along  its  free  margin  which  connect  it  externally  with 
the  dura  mater;  from  this  peculiarity,  and  from  its  sup- 
porting the  cord,  it  receives  the  name  of  ligamentum  denti- 
culatum,  or  membrana  dent  at  a. 

The  SPINAL  CORD  gives  off  thirty-one  pairs  of  nerves, 
arising  by  two  roots  and  passing  out  at  the  intervertebral 
foramina ;  they  are  divided  into  groups,  which  are  named 
cervical  (eight  pairs),  dorsal  (twelve  pairs),  lumbar  (five 
pairs),  sacral  (five  pairs),  and  coccygeal  (one  pair) ;  in. 
each  group  the  nerves  are  equal  to  the  number  of  vertebrae, 
except  in  the  cervical,  which  has  eight,  and  in  the  coccy- 
geal, which  has  but  one ;  as  the  cervical  nerves  exceed  the 
number  of  cervical  vertebrae,  the  lowest  nerve  of  each 
group  is  consequently  below  its  corresponding  vertebra. 

The  two  roots  which  blend  to  form  the  spinal  nerves  are 
called  anterior  and  posterior,  or  ganglion ic  and  a-ganglio- 
nic.  The  posterior  roots  are  the  largest,  and  are  each  fur- 
nished with  a  ganglion.  As  the  apertures  for  the  trans- 
mission of  the  nerves  are  not  opposite  their  points  of 
origin,  they  get  an  oblique  direction,  increasing  from  above 
downward ;  in  the  lumbar  and  sacral  region  their  direction 
is  vertical,  and  the  collection  of  the  roots  of  the  nerves 
around  the  filum  terminale,  which  constitutes  about  one- 
third  of  the  whole  length  of  the  cord,  is  called  the  cauda 
equina.  It  is  upon  these  lower  nerves  that  the  ganglion  of 
the  posterior  root  may  be  best^observed,  as  in  those  nerves 
given  off  more  nearly  opposite  their  foramina  it  often  lies 
in  the  intervertebral  canal.  The  first  nerve  sometimes 
wants  a  posterior  root. 

In  the  upper  part  of  the  canal,  the  spinal  portion  of  the 
spinal  accessory  nerve  (p.  83)  should  be  sought ;  it  arises 
by  fine  filaments  from  the  side  of  the  spinal  cord  as  low 
down  as  the  sixth  cervical  nerve,  and  lies  between  the  mem- 
brana dentata  and  the  posterior  roots  of  the  spinal  nerves, 
with  the  upper  of  which  it  is  sometimes  connected;  it 
finally  enters  the  skull  by  the  foramen  magnum,  to  join  the 
accessory  portion. 

The  spinal  cord  is  supplied  by  several  offsets  from  the  ver- 
tebral arteries;  near  their  termination  in  the  basilar  artery 
they  give  off  two  branches  which  unite  under  the  name  of 
the  anterior  spinal  artery;  this  is  continued  to  the  bottom  of 


136        ANATOMY    OP     UPPER    EXTREMITY,    ETC. 

the  spinal  canal  by  anastomoses  from  the  vertebral  arteries 
in  the  neck,  and  from  the  intercostal  and  lumbar  arteries. 
The  posterior  spinal  artery  is  also  derived  from  the  same 
source,  and  is  continued  down  the  posterior  aspect  of  the 
spinal  canal  by  anastomoses  from  the  same  branches  that 
reinforce  the  anterior  spinal  artery. 

The  veins  of  the  spinal  cord  are,  very  tortuous,  and  form 
a  plexus  on  its  surface,  emptying  their  contents  into  the 
vertebral,  intercostal,  lumbar,  and  sacral  veins. 

The  spinal  cord  should  be  hardened  in  alcohol  for  examination,  as, 
soon  after  death,  it  becomes  softened,  and  unfit  for  dissection. 

The  SPINAL  CORD  extends  from  the  medulla  oblongata  to 
the  first  or  second  lumbar  vertebra.  In  shape  it  is  a  flat- 
tened cylinder,  and  it  has  two  enlargements,  the  superior 
corresponding  to  the  origin  of  the  nerves  for  the  upper 
extremity,  and  the  inferior  enlargement  to  that  of  those  for 
the  lower  extremity.  The  cord  has  a  fissure  along  its  ante- 
rior surface,  and  another  along  its  posterior  surface ;  the 
anterior,  called  the  fissura  longitudinalis  anterior,  is  the 
widest,  and  the  posterior,  called  the  fissura  longitudinalis 
posterior,  is  the  deepest ;  a  lateral  fissure  also  exists  along 
the  line  of  origin  of  the  posterior  roots  of  the  spinal  nerves, 
and  another  has  been  described  as  being  found  along  the 
line  of  origin  of  the  anterior  roots. 

A  transverse  section  of  the  cord  will  show  that  each  of 
its  lateral  halves  is  divided  by  the  lateral  fissure  into  two 
parts,  that  in  front  of  the  fissure  being  called  the  antero- 
lateral  column,  and  that  behind,  the  posterior  column ;  it 
will  also  show  that  the  two  halves  of  the  cord  are  united 
hy  a  central  portion  which  limits  the  depth  of  the  longitu- 
dinal fissures,  and  is  called  the  commissure. 

A  transverse  section  of  the  cord  shows,  also,  that,  like 
the  brain,  it  is  composed  of  white  and  gray  substance,  but 
the  gray  portion  is  surrounded  by  the  white,  instead  of 
being  external,  as  in  the  encephalon.  The  gray  matter  is 
arranged,  in  each  half  of  the  cord,  in  the  form  of  a  crescent, 
the  horns  of  which  point  toward  the  roots  of  the  nerves ; 
the  convexity  looks  toward  the  commissure,  which  also  is 
chiefly  made  up  of  gray  matter.  The  posterior  horn  of  the 
crescent  reaches  to  the  fissure  along  the  attachment  of  the 
posterior  roots ;  the  anterior  horn  does  not  reach  to  the  ante- 
rior roots,  nor  does  it  form  so  sharp  a  point  as  the  posterior. 

The  deep  origin  of  the  spinal  nerves,  like  that  of  the 
cranial  nerves,  is  uncertain. 


SCAPULAR    REGION.  '137 

DISSECTION  VI. 

SCAPULAR   REGION. 

The  subject  should  be  restored  to  its  position  with  the  face  upper- 
most. All  the  muscles  which  attach  the  upper  extremity  to  the  thorax 
have,  with  a  single  exception,  been  examined,  and  if  they  have  been 
divided  it  will  be  held  only  by  the  clavicle  and  serratus  magnus 
muscle.  The  clavicle  should  be  divided  in  the  middle;  the  bundle 
of  nerves  and  the  artery  cut  through  opposite  the  second  rib,  and  tied 
in  a  bunch  to  the  fragment  of  clavicle  remaining.  This  exposes  the 
serratus  rnaguus  muscle. 

The  SERRATUS  MAGNUS  MUSCLE  covers  a  large  portion  of 
the  thoracic  parietes,  and  forms  the  inner  wall  of  the  axilla ; 
it  arises  by  nine  muscular  slips,  arranged  in  a  curved  line, 
th4  convexity  of  which  looks  forward,  from  the  anterior 
surface  of  eight  upper  ribs,  two  slips  being  attached  to  the 
second  rib,  and  the  lower  of  its  slips  indigitating  with  the 
external  oblique  muscle  of  the  abdomen ;  it  is  inserted  into 
the  whole  length  of  the  posterior  border  of  the  scapula. 
The  inferior  thoracic  and  subscapular  arteries  ramify  on 
the  surface  of  this  muscle,  and  the  long  thoracic  nerve  (p. 
103)  passes  dow/i  from  behind  the  axillary  plexus,  to  be  dis- 
tributed to  it. 

The  division  of  this  muscle  will  complete  the  separation  of  the 
upper  extremity  from  the  thorax.  In  accomplishing  this,  it  must  be 
remembered  that  some  important  branches  of  the  subclavian  artery 
are  distributed  to  the  dorsum  of  the  scapula,  and  these  should  be  so 
divided  as  not  to  interfere  with  their  further  examination. 

The  SUBSCAPULARIS  MUSCLE  lies  upon  the  inner  surface 
of  the  scapula,  covered  in  by  a  fibrous  lamina  which  is  but 
slightly  adherent  to  it;  this  being  removed,  it  will  be  found 
to  arise  from  the  inner  surface  of  that  bone,  except  at  its 
inferior  and  superior  angles ;  it  is  inserted  by  a  broad  flat 
tendon,  which  forms  a  part  of  the  capsular  ligament  of  the 
shoulder-joint,  into  the  lesser  tuberosity  of  the  humerus.  A 
band  of  fibres,  two  or  three  inches  in  length,  is  sometimes 
found  extending  from  the  scapula  to  the  neck  of  the  hu- 
merus, just  below  this  muscle.  The  belly  of  this  muscle  is 
intersected  longitudinally  by  aponeurotic  lamina?,  attached 
to  the  ridges  of  the  scapula.  The  subscapular  nerve,  arising 
from  the  posterior  part  of  the  brachial  plexus,  will  be  seen 
entering  this  muscle  immediately  after  its  origin,  penetrating 

12* 


138        ANATOMY    OP    UPPER    EXTREMITY,    ETC. 

the  superior  border  near  the  commencement  of  its  tendon ; 
a  small  branch  enters  at  the  lower  border,  and  a  third, 
accompanying  the  subscapular  arteiy,  is  eventually  dis- 
tributed to  the  latissimus  dorsi  muscle.  The  subscapular 
artery  will  also  be  noticed;  passing  along  the  lower  border, 
it  gives  a  branch  to  the  deep  surface  of  this  muscle,  and 
another  to  the  dorsuru  of  the  scapula,  and  anastomoses 
with  the  posterior  scapular  branch  of  the  subclavian  at  the 
inferior  angle  of  the  bone. 

The  TERES  MAJOR  MUSCLE  lies  below  the  sub-scapularis ; 
it  arises  on  the  dorsum  of  the  scapula  from  the  flat  surface 
constituting  its  inferior  angle,  and,  leaving  a  triangular 
interspace  between  it  and  the  lower  border  of  the  bone,  is 
inserted  by  a  broad  tendon,  conjoined  with  that  of  the 
latissimus  dorsi,  into  the  internal  ridge  of  the  bicipital 
groove  of  the  humerus.  A  synovial  bursa  exists  between 
the  conjoined  tendons. 

The  SUPRA-SPINATUS  MUSCLE  is  situated  on  the  dorsum 
of  the  scapula,  above  the  spine  of  that  bone;  occupying  the 
whole  of  the  supra-spinous  fossa,  from  the  walls  of  which 
it  arises ;  it  is  inserted  into  the  upper  facet  of  the  greater 
tuberosity  of  the  humerus,  by  a  flattened  tendon,  which 
forms  part  of  the  capsular  ligament  of  th^  shoulder-joint. 
Passing  through  the  supra-scapular  notch  will  be  seen  the 
supra-scapular  nerve,  a  branch  of  the  brachial  plexus, 
which  passes  beneath  this  muscle  to  supply  it,  and  then 
curves  round  the  external  border  of  the  spine,  to  be  dis- 
tributed to  the  infra-spinatus  muscle. 

To  trace  this  nerve,  as  well  as  to  follow  out  the  divided  extremity 
of  the  supra-scapular  artery,  the  acromion  process  should  be  sawed 
across  at  its  base,  and  removed ;  the  muscle  is  thus  wbolly  displayed, 
and  is  to  be  divided  near  its  tendon,  and  dissected  out  from  the  fossa, 
respecting  all  nervous  and  arterial  branches  which  may  be  exposed. 

The  supra-scapular  artery  is  a  branch  of  the  subclavian 
artery  (p.  58),  and  passes  over  the  ligament  of  the  supra- 
scapular  notch,  to  penetrate  beneath  the  supra-spinatns 
muscle,  which  it  supplies.  A  branch  winds  round  the  ante- 
rior border  of  the  spine  of  the  scapula,  to  inosculate  with 
the  dorsal  branch  of  the  subscapular,  and  with  the  branches 
of  the  posterior  scapular  distributed  on  the  dorsum  of  the 
bone. 

The  INFRA-SPINATUS  MUSCLE  occupies  the  infra-spinous 
fossa,  and  is  covered  by  a  dense  fascia,  which,  as  well  as 


BACK    OF    THE    A 11  M .  139 

the  remains  of  the  deltoid  muscle,  overlapping  its  anterior 
half,  must  be  removed.  It  arises  from  the  walls  of  the 
infra-spinous  fossa,  and  from  the  fascia  which  covers  it  ex- 
ternally ;  it  is  inserted  into  the  middle  facet  of  the  greater 
tuberosity  of  the  humerus  by  a  tendon  which  forms  part  of 
the  capsular  ligament  of  the  shoulder-joint.  Its  tendon  is 
at  first  concealed  by  the  muscular  fibres  which  overlap  it, 
each  half  of  the  muscle  being  folded  over  the  tendon,  from 
which  the  fibres  diverge  in  a  bipenniform  manner.  Passing 
along  its  outer  border  is  the  posterior  scapular  artery,  a 
branch  of  the  subclavian ;  at  the  inferior  angle  of  the 
scapula  this  artery  inosculates  with  the  subscapular,  and 
by  the  offsets  which  it  sends  to  the  infra-spinatus  muscle 
and  fossa,  unites  with  the  terminal  twigs  of  the  supra- 
scapular. 

The  TERES  MINOR  MUSCLE  lies  between  the  infra-spinatus 
and  the  teres  major  muscles ;  it  is  closely  connected  with 
the  former,  and  can  only  be  separated  from  it  artificially, 
so  that  the  dissector  is  sometimes  at  a  loss  to  define  this 
muscle,  though  he  may  be  perfectly  aware  of  its  locality. 
„  It  arises  from  the  inferior  border  of  the  scapula,  and  is  in- 
serted into  the  lower  facet  of  the  greater  tuberosity  of  the 
humerus,  its  tendon  forming  part  of  the  capsular  ligament 
of  the  shoulder-joint.  The  dorsal  branch  of  the  subscapular 
artery  curves  around  this  muscle,  just  outside  the  scapular 
head  of  the  triceps  muscle,  and  passes  to  the  infra-spinous 
fossa,  beneath  the  infra-spinatus  muscle,  which  it  supplies, 
and  where  it  inosculates  with  the  terminal  branches  of  the 
supra-scapular. 

BACK   OP    THE    ARM. 

The  TRICEPS  EXTENSOR  CUBITI  MUSCLE  makes  up  the 
whole  bulk  of  the  back  of  the  arm ;  it  has  three  points  of 
origin,  known  as  its  long,  middle,  and  short  heads.  The 
long  head  arises  from  the  inferior  border  of  the  scapula, 
just  below  the  glenoid  cavity ;  the  middle  head  arises  from 
all  the  shaft  of  the  humerus  below  its  greater  tuberosity, 
and  from  the  external  condyloid  ridge  and  the  intermuscu- 
lar  septum  connected  with  it ;  the  short  head  arises  from 
the  shaft  of  the  humerus  below  the  insertion  of  the  teres 
major,  and  from  the  internal  condyloid  ridge  and  its  inter- 
muscular  septum.  These  three  heads  conjoin,  to  be  inserted 
by  a  broad  aponeurotic  tendon  into  the  olecranon  process 


140       ANATOMY    OF    UPPER    EXTREMITY,   ETC. 

of  the  ulna ;  between  the  tendon  and  the  olecranon  is  a 
synovial  bursa. 

The  long  head  of  the  triceps  divides  the  triangular  space 
left  between  the  teres  major  and  the  subscapularis  muscle 
into  a  smaller  triangle  on  the  outer  side,  and  into  a  quad- 
rangular space  between  it  and  the  humerus  on  the  inner 
side.  Through  the  small  triangular  space  passes  the  dor- 
salis  scapulae  artery,  and  through  the  quadrangular  space 
the  posterior  circumflex  artery,  and  circumflex  nerve.  Be- 
neath the  belly  of  the  triceps,  and  between  it  and  the  shaft 
of  the  humerus,  pass  the  musculo-spiral  nerve  and  the  supe- 
rior profuuda  artery. 

The  triceps  muscle  must  be  divided  in  the  middle,  and  turned  up- 
ward and  downward  to  follow  out  the  course  of  this  artery  and  nerve. 


DISSECTION  VII. 

FRONT    OF    THE    FOREARM. 

An  incision  should  be  made  down  the  forearm  to  the  wrist,  and 
there  joined  by  a  short  transverse  one  ;  the  skin  is  to  be  removed  in 
such  a  way  as  to  permit  the  origin  of  the  veins  of  the  elbow  to  be 
seen,  as  well  as  the  terminations  of  the  cutaneous  nerves  (p.  107). 
The  muscles  of  the  forearm  are  surrounded  by  a  firm  aponeurosis, 
which  not  only  invests  them  collectively,  but  penetrates  between  them 
individually.  This  aponeurosis  is  to  be  divided  and  removed  ;  toward 
the  condyles  it  will  be  found  that  the  muscular  fibres  originate  from 
it,  and  where  they  do,  it  will  necessarily  be  left  adherent  to  them. 
The  muscles  are  best  isolated  from  one  another  by  commencing  at  the 
tendons,  and  tracing  their  separations  upward  to  the  elbow ;  the 
sheaths  of  the  muscles  and  the  cellular  tissue  lying  in  their  inter- 
spaces must  all  be  removed,  and  the  tendons  should  be  dissected  as 
cleanly  as  possible  ;  the  beautiful  appearance  they  present  when  pro- 
perly dissected  fully  repays  the  labor  spent  upon  them. 

The  tendon  of  the  biceps  muscle  divides  the  muscles  of 
the  forearm  into  an  external  and  an  internal  group,  each 
group  being  collectively  attached  to  the  condyle  of  the 
humerus  of  its  respective  side  by  a  common  tendon,  which 
also  sends  septa  between  the  muscles  ;  they  are  also  divided 
into  a  deep  and  a  superficial  layer.  In  separating  these 
muscles,  the  arteries  and  nerves  will  necessarily  come  into 
view.  It  will  be  seen  that  the  brachial  artery  dips  down- 
ward between  the  muscles,  and  divides  into  two  branches, 


FRONT    OP    THE    FOREARM.  141 

the  radial  and  ulnar ;  these  pass  down  the  arm  between  the 
muscles  to  the  wrist,  where  they  become  comparatively 
superficial,  and  then  enter  the  hand.  The  median  nerve  lies 
upon  the  inner  side  of  the  artery,  at  the  hollow  of  the  elbow, 
and  afterward  passes  down  the  middle  line  of  the  limb  in 
its  course  to  the  hand  ;  the  ulnar  nerve  will  be  found  on  the 
outside  of  the  ulnar  artery  in  its  lower  two-thirds;  the 
radial  nerve  also  accompanies  the  radial  artery  till  within 
three  inches  of  the  wrist,  where  it  becomes  cutaneous,  and 
divides  into  two  branches,  distributed  respectively  to  the 
back  of  the  thumb  and  dorsum  of  the  hand. 

The  PRONATOR  RADII  TERES  is  the,  first  muscle  next  the 
tendon  of  the  biceps  on  its  inner  side;  it  arises  by  two 
heads,  one  from  the  inner  condyle,  and  from  the  common 
tendon  above  mentioned,  the  other,  deeper,  and  not  to  be 
seen  in  the  present  stage  of  the  dissection,  from  the  coro- 
noid  process  of  the  ulna;  the  condyloid  attachment  some- 
times receives  additional  fibres  from  the  intermuscular 
septum  above  the  coiuiyle;  this  peculiarity  is  usually 
associated  with  the  existence  of  a  supra-condyloid  process 
(p.  106).  The  muscle  passes  obliquely  outward,  to  terminate 
in  a  flat  tendon  which  winds  round  the  radius,  and  is 
inserted  into  a  rough  surface  on  its  outer  side;  this  inser- 
tion cannot  be  seen  until  the  superficial  muscles  are 
removed.  The  median  nerve  passes  between  its  two  heads. 
The  FLEXOR  CARPI  RADIALIS,  arising  next  the  pronator 
radii  teres,  from  the  inner  condyle  and  the  common  tendon, 
becomes  tendinous  near  its  middle,  and  passing  through 
a  distinct  sheath,  outside  the  arch  of  the  annular  ligament, 
is  inserted  into  the  base  of  the  metacarpal  bone  of  the 
index  finger.  The  insertion  cannot  be  seen  till  the  hand  is 
dissected.  The  radial  artery  passes  along  the  outer  border 
of  the  lower  part  of  its  tendon. 

The  PALMARIS  LONGUS  MUSCLE  lies  on  the  inner  side  of 
the  flexor  carpi  radialis ;  it  has  a  small  belly  and  a  long 
tendon,  and  is  very  often  wanting;  it  arises  from  the  internal 
condyle  and  common  tendon,  and  continuing  down  the  cen- 
tre of  the  forearm  and  over  the  annular  ligament,  is  inserted 
into  the  palmar  fascia,  with  which  it  is  continuous. 

The  FLEXOR  CARPI  ULNARIS  passes  along  the  ulnar 
border  of  the  forearm,  arising  from  the  internal  condyle 
and  common  tendon,  and  also  from  the  inner  edge  of  the 
olecranon,  by  a  strong  but  thin  apoiieurosis,  underneath 
which  pass  the  ulnar  nerve,  and  the  recurrent  branch  of  the 


142        ANATOMY     OF     UPPER    EXTREMITY,    ETC. 

ulnar  artery;    its   tendon  receives    short   muscular  fibre 
nearly  down  to  the  point  of  its  insertion,  which  is  into  th( 
pisiform  bone  and  base  of  the  metacarpal  bone  of  the  littlt 
linger.     At  its  upper  part  this  muscle  overlaps  the  ulnai 
artery  and  nerve;   below  the  middle  they  are  upon 
inner  side  of  its  tendon. 

The  flexor  carpi  radialis  and  palmaris  longus  muscles  must  be 
divided  in  their  middle  and  the  two  ends  reflected,  as,  at  their  upper 
part,  they  cover  up  the  muscle  next  to  be  dissected.  The  numerous 
branches  of  the  ulnar  artery  at  the  elbow  should  be  carefully  preserved. 

The  FLEXOR  SUBLIMIS  DIGITORUM  forms  a  large  part  of 
the  muscular  mass  arising  from  the  inner  condyle;  it  also 
arises  from  the  coronoid  process  of  the  ulna  and  the  oblique 
line  of  the  radius ;  inferiority  it  divides  into  four  tendons 
which  pass  beneath  the  annular  ligament  to  be  inserted  into 
the  bases  of  the  second  phalanges  of  the  fingers,  as  will  be 
seen  in  the  dissection  of  the  hand.  Beneath  the  annular 
ligament  the  tendons  are  provided  with  a  synovial  mem- 
brane. A  muscular  slip  often  connects  this  muscle  with 
the  flexor  profundus,  or  the  flexor  longus  pollicis. 

The  upper  part  of  the  flexor  sublimis,  where  it  arises 
from  the  radius,  is  covered  by  the  pronator  radii  teres,  the 
tendinous  insertion  of  which,  winding  round  the  radius,  as 
well  as  its  coronoid  head,  can  now  be  seen.  The  tendon  of 
the  biceps  may  also  be  followed  between  the  muscles  to  its 
insertion  into  the  tubercle  of  the  radius.  The  brachialis 
anticus  will  likewise  be  exposed  so  that  its  insertion  into 
the  coronoid  process  of  the  ulna  can  be  examined.  None 
of  these  insertions  could  be  seen  when  the  bellies  of  these 
muscles  were  dissected. 

The  SUPINATOR  LONGUS  MUSCLE  gives  the  rounded  out- 
line characteristic  of  the  outer  side  of  the  forearm ;  it 
arises  from  the  humerus  on  its  outer  side,  nearly  as  high 
as  the  insertion  of  the  deltoid  muscle,  and  from  the  external 
condyloid  ridge ;  it  passes  down  the  radial  side  of  the  fore- 
arm and  is  inserted  by  a  flattened  tendon  into  the  external 
border  of  the  radius,  just  above  the  base  of  its  styloid 
process. 

The  RADIAL  ARTERY,  with  its  venae  comites,  lies  upon 
the  inner  side  of  the  last-named  muscle  at  its  upper  part, 
and  between  it  and  the  pronator  radii  teres;  lower  down 
it  lies  between  the  supinator  longus  and  flexor  carpi  radi- 
alis ;  at  its  upper  part  it  gives  off  the  radial  recurrent 


FRONT    OF    THE    FOREARM.  143 

branch,  which,  turning  backward  beneath  the  belly  of  the 
snpinator  longus,  sends  off  numerous  muscular  twigs  and 
inosculates  with  the  superior  profunda  branch  of  the  bra- 
chial ;  in  its  course  to  the  wrist  it  gives  off  many  muscular 
offsets,  and,  at  the  wrist,  an  anterior  and  posterior  carpal 
branch,  which  pass  transversely  across  in  front  and  behind, 
anastomose  with  similar  branches  from  the  ulnar  artery, 
e  superficialis  voids  branch  arises  from  an  uncertain  point 

tear  the  wrist,  and  passes  on  to  the  ball  of  the  thumb, 
there  to  lose  itself  in  the  muscles  or  to  join  with  the  super- 
ficial palmar  arch;  when  given  off  high  up,  it  occasionally 
furnishes  one  or  two  digital  branches.  Having  reached  the 
wrist,  the  radial  artery  winds  round  the  base  of  the  meta- 
carpal  bone  of  the  thumb,  beneath  its  extensor  tendons,  to 
enter  the  palm  of  the  hand  between  the  two  heads  of  the 

irst  dorsal  interosseous   muscle;   occasionally  it   curves 
mud  the  radius  higher  up  than  this,  and  sometimes  it 
isses  directly  over  the  annular  ligament  into  the  palm  ; 
its  whole  course  may  also  be  superficial,  owing  to  its  high 

livision  from  the  brachial  (p.  106).    The  radial  artery  often- 

imes  presents,  especially  in  old  and  fat  subjects,  a  series 
flexuosities  attended   by  dilatation;    this  condition  is 

isually  accompanied  by  a  deposit  of  calcareous  matter 
in  the  arterial  walls,  varying  in  quantity;  the  same  thing 
may  be  noticed  in  other  arteries,  and  in  these  cases,  ossific, 
or  atheromatous  deposits,  will  be  found  to  a  considerable 
extent  in  the  upper  part  of  the  aorta. 

The  RADIAL  NERVE  is  the  larger  of  the  two  branches 
into  which  the  musculo-spiral  nerve  divides  in  front  of  the 
external  condyle;  it  accompanies  the  radial  artery  upon 
its  outer  side  beneath  the  supinator  longus  muscle ;  near 
the  wrist  it  passes  under  the  tendon  of  the  supinator, 
becomes  cutaneous,  and  divides  into  two  branches,  one  for 
the  back  of  the  thumb,  and  the  other  for  the  back  of  the 
hand. 

The  MEDIAN  NERVE  passes  between  the  two  heads  of  the 
pronator  radii  teres,  and  beneath  the  flexor  sublimis  digi- 
torum,  where  it  gives  off  the  anterior  interosseous  and 
muscular  branches ;  near  the  wrist  it  becomes  superficial, 
appearing  along  the  outer  border  of  the  tendons  of  the  lat- 
ter muscle ;  it  here  gives  off  a  superficial  palmar  branch, 
which  passes  over  the  annular  ligament  to  the  muscles  and 
integument  of  the  ball  of  the  thumb,  while  the  main  part 
of  the  nerve  continues  beneath  the  ligament  to  the  fingers. 


144        ANATOMY    OF     UPPER    EXTREMITY,    ETC. 

When  the  brachial  artery  passes  behind  the  supra-condy- 
loid  process  (p.  106),  the  median  nerve  always  follows  ii 
but  the  nerve  may  curve  around  the  process  without  th< 
artery ;  if  the  process  exists  the  nerve  invariabty  deviate 
from  its  course,  the  artery  generally,  but  not  always.     The 
median  nerve  is  sometimes  accompanied  by  an  artery  of 
considerable  size,  called  the  median  artery,  given  off  by  the 
anterior  interosseous  or  ulnar  ;  it  accompanies  the  nerve  to 
the  hand,  where  it  joins  one  of  the  palmar  arches,  or  one 
of  the  digital  branches. 

The  ULNAR  ARTERY,  at  its  origin  from  the  brachial,  lies 
upon  the  brachialis  anticus  muscle ;  it  then  dips  beneath 
the  flexor  sublimis  digitorum,  crosses  obliquely  to  the 
inside  of  the  arm,  and,  at  its  middle  third,  becomes  more 
superficial,  lying  between  the  tendons  of  the  flexor  sublimis 
and  flexor  carpi  ulnaris,  to  which  it  gives  several  muscular 
twigs ;  it  crosses  the  annular  ligament  under  a  strong 
fascia  thrown  over  it  from  the  pisiform  bone,  and  there 
forms  the  superficial  palmar  arch,  covered  in  by  the  palmar 
fascia.  Just  beyond  its  origin  it  gives  off  the  anterior 
ulnar  recurrent  branch,  which,  passing  backward  between 
the  brachialis  anticus  and  pronator  radii  teres  muscles, 
breaks  up  into  muscular  branches,  and  inosculates  with 
the  inferior  profunda  and  anastomotica  magna  of  the  bra- 
chial. The  posterior  ulnar  recurrent  branch  sometimes 
originates  by  a  common  trunk  with  the  preceding,  and 
sometimes  is  given  off  a  little  lower  down ;  it  passes  be- 
neath the  superficial  muscles  of  the  inside  of  the  forearm, 
and  emerging  beneath  the  tendon  of  the  flexor  carpi  ulnaris 
at  the  side  of  the  ulnar  nerve,  anastomoses  with  the  inferior 
profunda  and  anastomotic  arteries.  The  common  inter- 
osseous  artery  is  given  off  just  below  these  branches,  and 
its  divisions  will  be  hereafter  described.  The  ulnar  artery 
gives  off  only  muscular  branches  until  it  reaches  the  wrist, 
where  it  furnishes  an  anterior  carpal  branch  to  the  front, 
and  a  posterior  carpal  branch  to  the  back  of  the  wrist, 
both  of  which  pass  transversely  across  to  anastomose 
with  similar  branches  from  the  radial.  In  cases  of  high 
division,  the  ulnar  artery  is  usually  superficial  in  the  fore- 
arm. 

The  ulnar  artery  is  accompanied  by  two  venae  comites. 

The  ULNAR  NERVE,  after  passing  under  the  origin  of  the 
flexor  carpi  ulnaris,  continues  beneath  that  muscle  to  about 
the  middle  of  the  forearm,  where  it  joins  the  arterjT,  and 


FRONT    OF    THE    FOREARM.  145 

descends  along  its  outer  side  to  the  wrist :  it  here  gives  off 
a  branch  which  supplies  the  back  of  the  hand,  and  then, 
with  the  artery,  passes  over  the  annular  ligament  to  the 
palm  of  the  hand. 

The  flexor  sublimis,  flexor  carpi  ulnaris,  and  supinator  longus  mus- 
cles, are  now  to  be  divided  across  their  tendons,  and  their  muscular 
bellies  reflected.  The  pronator  radii  teres  may  be  drawn  to  one  side 
by  hooks.  The  arteries  and  nerves  should  remain  undivided. 

The  FLEXOR  PROFUNDUS  DIGITORUM  lies  upon  the  ulna, 
and  arises  from  the  upper  two-thirds  of  that  bone,  and  from 
the  interosseous  membrane ;  it  divides  into  four  tendons, 
which  are  not,  however,  separable  above  the  annular  liga- 
ment, beneath  which  they  pass,  and  are  inserted  into  the 
bases  of  the  last  phalanges,  having  perforated  the  tendons 
of  the  flexor  sublimis. 

The  FLEXOR  LONGUS  POLLICIS  lies  beneath  the  snpinator 
longus  muscle,  and  upon  the  radius;  it  arises  from  the 
upper  two-thirds  of  that  bone,  from  the  coronoid  process 
of  the  ulna,  and  ^from  the  interosseous  membrane  ;  its 
tendon  passes  beneath  the  annular  ligament,  and  is  in- 
serted into  the  last  phalanx  of  the  thumb. 

The  COMMON  INTEROSSEOUS  ARTERY,  after  arising  from 
the  ulnar,  quickly  divides  into  two  branches,  anterior  and 
posterior.  The  anterior  branch  passes  down  the  arm,  be- 
tween or  in  the  deep  flexor  muscles,  in  close  relation  to  the 
interosseous  membrane  ;  beneath  the  pronator  quadratus 
muscle  the  artery  passes  through  this  membrane  to  anasto- 
mose with  the  posterior  carpal  branches  of  the  ulnar  and 
radial.  The  posterior  branch  passes  through  the  inter- 
osseous membrane  at  its  upper  part,  and  is  distributed  to 
the  posterior  aspect  of  the  arm. 

The  anterior  interosseous  nerve,  a  branch  of  the  median, 
accompanies  the  anterior  interosseous  artery,  and  termi- 
nates in  the  pronator  quadratus  muscle. 

The  PRONATOR  QUADRATUS  MUSCLE  is  a  flat  quadrilateral 
muscle,  stretched  transversely  across  the  lower  part  of  the 
bones  of  the  forearm ;  it  arises  from  the  anterior  surface 
and  border  of  the  ulna,  and  is  inserted  into  the  anterior  sur- 
face of  the  radius  ;  the  insertion  is  usually  a  little  narrower 
than  its  origin. 


13 


146        ANATOMY     OF    UPPER    EXTREMITY,    ETC. 

DISSECTION  Till. 

BACK    OF    THE   FOREARM  AND    HAND. 

The  skin  is  to  be  removed  from  the  back  of  the  arm  and  hand. 
The  muscles  are  covered  in  by  a  dense  fascia  continuous  with  that  of 
the  front  of  the  arm  ;  this  may  be  removed  at  its  lower  part,  but  it  is 
adherent  to  the  bellies  of  the  muscles  above  ;  the  muscles  should  be 
separated  by  tracing  them  upward  from  their  tendons.  The  back  of 
the  arm  is  more  difficult  to  dissect  neatly  than  the  front. 

Before  commencing  the  dissection  of  the  muscles,  the 
dorsal  branch  of  the  radial  nerve  should  be  followed  out. 
It  becomes  cutaneous  at  the  lower  third  of  the  radius,  and 
divides  into  two  branches  ;  one  of  which  is  distributed  to 
the  radial  border  and  ball  of  the  thumb  ;  the  other  divides 
into  dorsal  digital  branches  and  supplies  the  remaining 
side  of  the  thumb,  both  sides  of  the  next  two  fingers,  and 
half  the  ring  finger.  The  dorsal  branch  of  the  ulnar  nerve, 
appearing  near  the  styloid  process  of  the  ulna,  supplies 
both  sides  of  the  little  finger,  and  the  contiguous  side  of 
the  ring  finger  upon  their  dorsal  surfaces. 

The  muscles  of  the  back  of  the  arm  are  divided  into  two 
layers  ;  the  separation  is  not  well  defined,  and  the  muscles 
are  not  so  voluminous  as  those  of  the  front  of  the  arm. 

The  EXTENSOR  CARPI  RADIALIS  LONGIOR  lies  upon  the 
radial  side  of  the  arm,  just  below  the  supinator  longus,  by 
which  it  is  partly  covered  ;  it  arises  from  the  external 
condyloid  ridge  of  the  humerus,  and  its  tendon  passes 
through  a  well-marked  groove  in  the  head  of  the  radius, 
which  is  covered  by  the  posterior  annular  ligament,  to  be 
inserted  into  the  base  of  the  metacarpal  bone  of  the  index 
finger.  The  radial  nerve  lies  along  the  outer  border  of  its 
tendon. 

The  EXTENSOR  CARPI  RADIALIS  BREVIOR  immediately 
succeeds  the  preceding  muscle,  and  is  partly  covered  by 
it ;  it  arises  from  the  outer  condyle  of  the  humerus,  and 
the  tendon  common  to  the  extensor  muscles  ;  it  forms  a 
tendon  closely  united  with  that  of  the  extensor  carpi  radi- 
alis  longior,  and  passes  through  the  same  groove  in  the 
radius,  beneath  the  annular  ligament ;  after  which  it  di- 
verges from  it,  and  is  inserted  into  the  base  of  the  meta- 
carpal bone  of  the  middle  finger.  The  tendons  of  both 
these  muscles  pass  beneath  the  extensor  tendons  of  the 
thumb. 


BACK    OF    THE    FOREARM    AND    HAND.  14t 

The  EXTENSOR  COMMUNIS  DIGITORUM  occupies  the  cen- 
tral portion  of  the  posterior  region  of  the  forearm ;  it 
arises  from  the  external  condyle  by  the  tendon  common  to 
the  extensor  muscles,  and  from  the  intermuscular  septa 
between  it  and  the  contiguous  muscles ;  at  the  lower  part 
of  the  arm  it  divides  into  three  tendons,  which  pass 
through  the  annular  ligament  in  a  compartment  with  the 
extensor  indicis  ;  escaping  from  the  ligament,  the  most 
internal  tendon  divides  into  two,  and  the  four  tendons  pass 
along  the  dorsum  of  the  hand,  forming  a  flattened  sheath 
for  the  back  of  each  finger.  Opposite  the  first  phalangeal 
articulation  this  expanded  tendon  divides  into  three  slips  ; 
the  central  one  is  inserted  into  the  base  of  the  second 
phalanx,  the  two  lateral  continue  onward  and  are  inserted 
into  the  dorsal  surface  of  the  last  phalanx.  Oblique  ten- 
dinous bands  connect  the  tendons  with  each  other  on  the 
back  of  the  hand,  and  upon  the  fingers  they  are  reinforced 
)y  tendinous  slips  from  the  lumbricales  and  interossei  mus- 

The  EXTENSOR  MINIMI  DIGITI  is  generally  a  part  of  the 

:tensor  communis ;  occasionally  it  is  separable  from  it. 
[ts  origin  is  the  same,  and  it  passes  through  a  separate  ring 
)f  the  annular  ligament ;  its  tendon,  which  is  split  into  two 
directly  afterward,  terminates  in  an  expansion  on  the  back 
of  the  little  finger. 

The  EXTENSOR  CARPI  ULNARIS  arises  from  the  external 
condyle,  and  the  common  tendon  of  the  extensors,  and 
from  the  upper  part  of  the  ulna ;  its  tendon  passes  through 
a  separate  sheath  of  the  annular  ligament,  just  over  the  car- 
pal end  of  the  ulna,  to  be  inserted  into  the  base  of  the 
metacarpal  bone  of  the  little  finger. 

The  ANCONEUS  MUSCLE  is  a  small  triangular  muscle 
placed  upon  the  posterior  part  of  the  elbow-joint,  which  it 
partly  covers,  and  is  sometimes  considered  as  a  part  of  the 
triceps  extensor  cubiti ;  it  arises  from  the  outer  condyle 
by  a  distinct  tendon  posterior  to  the  common  tendon  of 
the  extensor  muscles,  and  is  inserted  into  the  radial  side  of 
the  olecranon  and  the  adjacent  surface  of  the  ulna. 

The  extensor  muscles  of  the  arm,  which  have  been  described,  are 
now  to  be  divided  in  the  middle,  and  their  two  ends  reflected ;  how- 
ever careful  he  may  have  been,  the  student  must  expect  the  deep 
layer  of  muscles  to  present  a  ragged  appearance. 

The  posterior  interosseous  artery  perforates  the  interos- 


148        ANATOMY    OF    UPPER    EXTREMITY,    ETC. 

seous  membrane  at  its  upper  part,  and  appears  between  the 
supinator  brevis  and  the  extensor  ossis  metacarpi  muscles  ; 
it  descends  between  the  deep  and  superficial  layers  of  mus- 
cles, supplying  them  with  muscular  branches,  and  anasto- 
moses with  the  posterior  carpal  arteries  of  the  radial  and 
ulnar,  and  with  the  terminal  twigs  of  the  anterior  inter- 
osseous  ;  at  its  upper  part  it  gives  off  a  recurrent  branch, 
which  passes  beneath  the  anconeus  muscle  to  supply  the 
elbow-joint,  and  anastomose  with  a  branch  of  the  superior 
profunda  of  the  brachial. 

The  posterior  interosseous  nerve  is  given  off,  in  front  of 
the  outer  condyle,  from  the  musculo-spiral  nerve ;  it  passes 
through  the  fibres  of  the  supinator  brevis  to  descend  the 
back  of  the  arm  between  the  two  layers  of  muscles  as  far  as 
the  middle  of  the  forearm,  where  it  sinks  beneath  the  ex- 
tensor secundi  internodii  pollicis,  and  is  distributed  to  the 
back  of  the  carpus;  sometimes  it  has  a  gangliform  swelling 
at  its  termination. 

The  SUPINATOR  BREVIS  MUSCLE  is  a  small  muscle  at  the 
upper  part  of  the  arm,  the  fibres  of  which  pass  obliquely 
round  the  upper  third  of  the  radius ;  it  arises  from  the  ex- 
ternal lateral  and  the  orbicular  ligaments,  and  from  about 
two  inches  of  the  upper  part  of  the  ulna,  and  is  inserted 
into  the  oblique  line  on  the  upper  part  of  the  radius,  except 
at  its  inner  part. 

The  EXTENSOR  Ossis  METACARPI  POLLICIS  lies  next  below 
the  supinator  brevis,  and  is  sometimes  united  with  it ;  it 
arises  from  the  posterior  surface  of  the  radius,  from  the 
ulna,  and  from  the  intervening  interosseous  membrane ;  it 
forms  a  large  belly,  the  tendon  of  which,  passing  through 
the  outer  compartment  of  the  posterior  annular  ligament, 
and  in  a  groove  of  the  radius  common  to  it  and  the  exten- 
sor primi  internodii  pollicis,  is  inserted  into  the  base  of  the 
metacarpal  bone  of  the  thumb. 

The  EXTENSOR  PRIMI  INTERNODII  POLLICIS  is  the  smallest 
muscle  of  the  deep  la}Ter,  and  its  tendon  is  closely  connected 
with  that  of  the  preceding  muscle ;  it  arises  from  the  radius 
and  interosseous  membrane  just  below  ths  origin  of  that 
muscle,  and  passing  through  the  same  compartment  in  the 
annular  ligament,  is  inserted  into  the  base  of  the  first  pha- 
lanx of  the  thumb. 

The  EXTENSOR  SECUNDI  INTERNODII  POLLICIS  lies  next 
below,  and  is  partly  covered  by  the  preceding  muscle ;  it 
arises  from  the  posterior  surface  of  the  ulna,  and  from  the  in- 


BACK     OF    THE    FOREARM    AND     HAND.  149 

terosseous  membrane,  and  descends  obliquely  to  the  thumb ; 
its  tendon,  crossing  the  radial  artery  and  the  extensor  mus- 
cles of  the  wrist,  passes  through  a  special  sheath  in  the 
annular  ligament,  and  in  a  groove  in  the  radius,  to  be  in- 
serted into  the  base  of  the  second  phalanx  of  the  thumb. 
The  little  triangular  interval  left  between  the  tendon  of  this 
muscle  and  the  parallel  tendons  of  the  two  preceding  mus- 
cles, has  been  called  the  "anatomist's  snuff-box;"  forced 
abduction  of  the  thumb  will  reveal  the  depression  to  which 
this  name  is  given. 

The  EXTENSOR  INDICTS  is  the  lowest  muscle  toward  the 
wrist ;  it  arises  from  the  shaft  of  the  ulna,  usually  below 
the  middle ;  its  tendon  passes  through  the  annular  ligament 
with  the  common  extensor  of  the  fingers,  and  uniting  with 
the  tendon  of  that  muscle  going  to  the  forefinger,  is  inserted 
with  it  into  the  second  and  third  phalanges. 

The  POSTERIOR  ANNULAR  LIGAMENT  is  formed  from  the 
deep  fascia  of  the  arm,  and,  if  divided  over  the  tendons 
passing  through  it,  will  be  found  to  have  six  separate 
canals,  lined  with  synovial  membrane ;  with  the  exception 
^of  that  for  the  extensor  minimi  digiti,  which  lies  in  the 
interval  between  the  two  bones,  each  of  these  canals  has 
a  corresponding  groove  in  the  radius  or  ulna ;  between  each 
of  the  canals,  the  ligament  is  firmly  attached  to  the  bone 
beneath. 

The  radial  artery  will  be  found  passing  round  the  lower 
end  of  the  radius,  beneath  the  extensor  tendons  of  the 
thumb,  to  the  space  between  the  thumb  and  forefinger, 
where  it  passes  between  the  two  heads  of  the  first  dorsal 
interosseous  muscle,  and  penetrates  the  palm  of  the  hand. 
Before  disappearing,  it  gives  off  the  dorsal  carpal  branch, 
which  crosses  transversely  beneath  the  extensor  tendons, 
to  join  a  similar  branch  from  the  ulnar  arteiy.  From  the 
arch  thus  formed,  dorsal  interosseous  arteries  are  given  off 
to  the  third  and  fourth  interosseous  spaces  ;  the  metacarpal, 
or  first  dorsal  interosseous,  larger  than  the  others,  passes 
upward,  in  the  space  between  the  first  and  second  metacarpal 
bones,  anastomosing,  as  do  the  others,  with  the  perforating 
branch  of  the  deep  palmar  arch ;  at  the  cleft  of  the  index  and 
middle  fingers  it  ends  by  joining  with  the  digital  branch  of 
the  superficial  palmar  arch.  The  radial  artery  also  gives  off 
two  small  dorsal  branches  to  the  thumb,  and  a  dorsal 
branch  to  the  index  finger. 

In  addition  to  its  posterior  carpal  branch,  the  ulnar 

13* 


150       ANATOMY    OF    UPPER    EXTREMITY,    ETC. 

artery  sends  a  metacarpal   branch  along   the  metacarpal 
bone  of  the  little  finger. 

The  DORSAL  INTEROSSEOUS  MUSCLES  are  four  in  number, 
occupying  the  spaces  between  the  metacarpal  bones,  and 
arising  by  a  double  head  from  the  lateral  surfaces  of  the 
two  bones  between  which  they  lie.  The  first  is  larger  than 
the  others,  and  is  called  the  abductor  indicts ;  it  is  inserted 
into  the  radial  side  of  the  first  phalanx  and.  the  extensor 
tendon  of  the  index  finger ;  the  radial  artery  passes  between 
its  heads ;  the  second  terminates  in  the  first  phalanx  and 
extensor  tendon  of  the  middle  finger  on  the  radial  side ; 
the  third  is  also  inserted  into  the  first  phalanx  and  ex- 
tensor tendon  of  the  middle  finger,  but  upon  its  ulnar 
side ;  the  fourth  is  inserted  into  the  first  phalanx  and  ex- 
tensor tendon  of  the  ring  finger  on  its  ulnar  side. 


DISSECTION  IX. 

PALM   OF    THE   HAND. 

To  dissect  tlie  hand,  the  fingers  and  thumb  should  be  separated 
widely  from  each  other  and  fastened  to  the  table  by  pins  driven 
through  the  skin  at  the  tip  of  each  finger.  An  incision  made  down 
the  middle  of  the  palm,  and  another  transversely  across  the  roots 
of  the  fingers,  from  which  others  can  be  carried  down  the  length  of 
each,  will  permit  the  removal  of  the  thick  skin  and  fat  covering  and 
penetrating  the  perforations  of  the  dense  fascia  radiating  from  the 
annular  ligament  to  the  fingers.  Upon  the  ulnar  side  the  student 
must  respect  the  palmaris  brevis  muscle,  composed  of  a  few  bundles 
of  transverse  fibres  lying  in  the  fat  just  beneath  the  integument,  and 
he  must  be  careful  not  to  destroy  the  transverse  ligament,  which 
Stretches  between  the  commissures  of  the  fingers. 

The  PALMARIS  BREVIS  MUSCLE  consists  of  a  small  though 
variable  number  of  transverse  fibres,  arising  from  the 
palmar  fascia  and  annular  ligament ;  it  is  inserted  into 
the  integument  of  the  ulnar  border  of  the  hand. 

The  ulnar  nerve,  dividing  on  the  annular  ligament,  sends 
a  superficial  branch  to  the  palmaris  brevis  and  gives  off 
two  digital  nerves  which  supply  both  sides  of  the  little 
finger  and  the  contiguous  side  of  the  ring  finger.  A  deep 
branch  penetrates  between  the  abductor  and  flexor  minimi 
digiti  muscles,  then  passes  under  the  flexor  tendons,  accom- 
panying the  deep  palmar  arch,  and  is  distributed  to  the 


PALM     OP    THE     HAND.  151 

interossei  and  lumbricales  muscles,  and  to  the  muscles  of 
the  thumb. 

The  median  nerve  sends  an  offset  across  the  annular 
ligament  which  passes  down  the  middle  of  the  palm  and 
unites  with  one  of  the  superficial  branches  of  the  ulnar 
nerve. 

The  PALMAR  FASCIA,  continuous  with  the  anterior 
border  of  the  annular  ligament,  spreads  out  anteriorly, 
covering  in  the  tendons  and  vessels,  and  opposite  each 
finger  divides  into  slips  attached  to  the  sides  of  the  first 
phalanges ;  between  these,  emerge  the  tendons,  nerves, 
and  vessels  of  the  fingers ;  strong  transverse  fibres  attached 
to  the  phalanges  on  each  side,  called  the  transverse  liga- 
ment, form  a  framework  over  which  is  stretched  the  skin 
constituting  the  commissures  of  the*  fingers.  The  palmar 
fascia  'is  held  down  by  fibres  attached  along  the  metacarpal 
bones. 

The  palmar  fascia  is  to  be  removed  with  the  scissors,  preserving  the 
nerves  and  arteries  beneath  it ;  the  examination  of  the  muscles  of  the 
thumb  is  then  to  be  proceeded  with. 

The  ABDUCTOR  POLLICIS  is  the  most  superficial  muscle 
of  the  thumb  ;  it  is  flat  and  narrow,  and  arises  from  the 
annular  ligament  and  the  os  trapezium ;  it  is  inserted  into 
the  base  of  the  first  phalanx  of  the  thumb ;  it  is  oftentimes 
connected  at  its  origin  with  a  slip  from  the  tendon  of  the 
extensor  ossis  metacarpi  pollicis. 

The  FLEXOR  Ossis  METACARPI  POLLICIS,  or  OPPONENS 
POLLICIS  MUSCLE,  lies  beneath  the  preceding,  its  fibres  pro- 
jecting on  both  sides ;  it  arises  from  the  annular  ligament 
and  os  trapezium,  and  is  inserted  into  the  whole  length  of 
the  metacarpal  bone  of  the  thumb. 

The  superficialis  volae  branch  of  the  radial  artery  crosses 
these  muscles  at  their  origin,  and  either  terminates  in  their 
fibres,  or  continues  on  to  inosculate  with,  the  terminal  part 
of  the  superficial  arch  of  the  ulnar  artery.  It  is  not  always 
present. 

The  FLEXOR  BREVIS  POLLICIS  is  the  largest  of  the  mus- 
cles of  the  thumb ;  it  has  two  points  of  origin,  one  from 
the  annular  ligament  and  trapezium,  the  other  from  the 
os  trapezoides  and  os  magnum  ;  between  these  two  portions 
passes  the  tendon  of  the  long  flexor  of  the  thumb,  which  it 
will  be  remembered  is  a  brachial  muscle  (p.  145);  they  then 
unite  into  one  mass,  to  be  inserted  by  two  heads  into  the 


152        ANATOMY    OF    UPPER    EXTREMITY,    ETC. 

sides  of  the  base  of  the  first  phalanx  of  the  thumb,  the 
inner  being  united  with  the  adductor  pollicis,  and  the  outer 
with  the  abductor  pollicis ;  a  sesamoid  bone  is  connected 
with  each  at  its  insertion.  A  branch  from  the  median 
nerve  supplies  the  outer  part  of  the  flexor  and  the  abductor 
and  opponens  pollicis  muscles. 

The  examination  of  the  adductor  pollicis  muscle  is 
necessarily  deferred  to  a  later  period  of  the  dissection. 

The  palmaris  brevis  being  removed,  the  most  superfici 
of  the  remaining  muscles  of  the  little  finger  is  the  AB- 
DUCTOR MINIMI  DIGITI  ;  it  arises  from  the  pisiform  bone 
and  the  tendon  of  the  flexor  carpi  uhiaris,  and  is  inserted 
into  the  ulnar  side  of  the  base  of  the  first  phalanx  of  the 
little  finger.  This  muscle  may  arise  from  the  fascia  of  the 
forearm  with  a  length  of  four  inches.  A  branch  from  the 
ulnar  artery,  called  the  communicating,  and  a  deep  branch 
of  the  ulnar  nerve,  pass  between  this  muscle  and  the  one 
beneath  it. 

The  FLEXOR  BREVIS  MINIMI  DIGITI  lies  beneath  the 
preceding,  of  which  it  appears  to  be  a  part ;  it  arises  from 
the  unciform  bone  and  from  the  annular  ligament,  and  is 
inserted  into  the*base  of  the  first  phalanx  of  the  little 
finger.  This  muscle  is  sometimes  wanting. 

The  FLEXOR  Ossis  METACARPI,  ADDUCTOR,  or  OPPONENS 
MINIMI  DIGITI  is  partty  overlaid  by  the  preceding  muscles; 
it  arises  from  the  annular  ligament  and  from  the  process  of 
the  unciform  bone,  and  is  inserted  into  the  whole  length  of 
the  metacarpal  bone  of  the  little  finger. 

The  continuation  of  the  ulnar  artery  in  the  palm  of  the 
hand  is  called  the  superficial  palmar  arch ;  it  is  covered  in 
by  the  palmar  fascia,  and  lies  across  the  flexor  tendons  of 
the  fingers  and  the  digital  branches  of  the  median  nerve  ;  it 
gives  off  a  deep  communicating  branch,  which  passes  be- 
tween the  abductor  and  flexor  minimi  digiti,  to  inosculate,  as 
will  be  seen  hereafter,  with  the  deep  arch  of  the  radial  artery ; 
it  supplies  both  sides  of  the  three  inner  fingers,  and  one 
side  of  the  index  finger,  with  digital  branches ;  these  arise 
opposite  the  interosseous  spaces  by  single  trunks,  which 
bifurcate  to  supply  the  contiguous  sides  of  two  fingers, 
those  of  the  same  finger  uniting  at  its  extremity;  the 
branch  to  the  outer  side  of  the  little  finger  arises  singly. 
Near  the  roots  of  the  finger  the  digital  arteries  receive 
communicating  branches  from  the  deep  arch ;  but  the  artery 
to  the  little  finger  gets  its  communicating  branch  from  the 


PALM    OP    THE     HAND.  153 

deep  arch  about  the  middle  of  the  hand.  The  terminal 
part  of  the  superficial  artery  unites  with  the  superficialis 
volse,  and  with  the  branch  of  the  radial  artery  which  sup- 
plies the  radial  side  of  the  forefinger. 

The  median  nerve,  after  emerging  from  beneath  the  annu- 
lar ligament,  divides  into  two  trunks ;  the  external  of  these, 
besides  giving  off  a  muscular  branch  to  the  muscles  of  the 
thumb  (p.  143),  divides  into  three  digital  branches,  which 
go  to  the  two  sides  of  the  thumb  and  the  radial  side  of  the 
forefinger;  the  internal  trunk  divides  into  two  branches 
which  bifurcate  to  supply  the  contiguous  sides  of  the  fore  and 
middle,  and  middle  and  ring  fingers.  The  digital  nerves  pass 
down  the  sides  of  the  fingers,  superficially  to  the  arteries, 
and  terminate  by  filaments  in  the  pulp  at  their  extremities. 

The  ANTERIOR  ANNULAR  LIGAMENT  is  a  firm  ligamentous 
band,  beneath  which  pass  the  tendons  of  the  flexor  muscles; 
it  is  attached  to  the  trapezium  and  scaphoid  bones  on  one 
side,  and  to  the  unciform  and  the  pisiform  bones  on  the 
other.  The  canal  formed  by  this  ligament  is  lubricated 
by  a  synovial  membrane,  which  surrounds  each  tendon 
separately,  and  is  prolonged  both  above  and  below  the 
ligament,  sometimes  even  as  far  as  the  fingers,  where  it 
communicates  with  the  synovial  membrane  of  the  sheaths 
of  some  of  the  tendons;  this  communication  has  been  de- 
monstrated to  be  nearly  constant  in  the  tendons  of  the 
thumb  and  little  finger;  with  the  others  it  is  only  of  occa- 
sional occurrence.  This  continuity  in  their  synovial  mem- 
branes explains  the  terrible  consequences  which  sometimes 
follow  phlegmonous  inflammation  of  the  fingers.  The 
synovial  sac  of  the  wrist  and  fingers  may  be  demonstrated 
by  insufflation. 

The  annular  ligament  is  now  to  be  divided  ;  the  median  and  ulnar 
nerves  are  also  to  be  cut  through,  and  turned  over  toward  the  fingers. 

The  tendons  of  the  flexor  sublimis  digitorum  muscle  are 
superficial  to  those  of  the  deep;  these  enter  the  sheaths  of 
the  fingers,  and  are  inserted  by  two  processes  into  the  mar- 
gins of  the  second  phalanges  at  about  their  middle,  being- 
split  opposite  the  first  phalanges  for  the  passage  of  the 
deep  flexor  tendons.  The  sheath  of  the  tendons  consists 
of  transverse  tendinous  fibres  attached  to  the  sides  of  the 
first  and  second  phalanges;  in  front  of  the  articulations  the 
sheaths  are  either  wanting  or  imperfectly  developed ;  they 
firti  lined  by  a  synovial  membrane. 


154        ANATOMY    OF    UPPER    EXTREMITY,    ETC. 

The  tendons  of  the  flexor  sublimis  are  to  be  divided  and  reflected 
toward  the  fingers. 

The  LUMBRICALES  MUSCLES  are  small  and  delicate  mus- 
cular slips  connected  with  the  deep  flexor  tendons ;  they 
are  usually  four   in  number,  sometimes   only  three,  and 
occasionally  as  many  as  six ;  they  arise  from  the  radii 
side  of  the  tendon,  near  the  annular   ligament,  and  ai 
partly  concealed   by  the   tendons  of  the  flexor   sublimis 
digitorum;  they  are  inserted  into  the  tendinous  expansions 
of  the  extensor  muscles  covering  the  backs  of  the  fingers. 

The  tendons  of  the  flexor  profundus  digitorum  muscle, 
the  division  of  which  takes  place  in  the  palm,  enter  the 
sheaths  of  the  tendons  of  the  flexor  sublimis,  pass  through 
the  split  in  these,  and  continue  onward  to  be  inserted  into 
the  bases  of  the  last  phalanges.  They  are  attached  to  the 
phalanges  and  the  capsules  of  the  finger-joints  along  the 
median  line,  by  membranous  folds,  given  off  from  their  pos- 
terior surface,  and  which  contain  elastic  tissue ;  these  are 
called  the  hgamenta  brevia,  or  vincula  subflava,  and  are 
supposed  to  hold  the  tendons  down  when  the  fingers  are 
bent. 

The  tendon  of  the  flexor  longus  pollicis  passes  through 
the  annular  ligament,  externally  to  those  of  the  flexor  pro- 
fundus, and  turns  outward  between  the  heads  of  the  flexor 
brevis  pollicis  to  be  inserted  into  the  last  phalanx  of  the 
thumb. 

The  deep  flexor  tendons  are  to  be  divided  and  reflected  toward  the 
fingers. 

The  ADDUCTOR  POLLICIS  MUSCLE,  obscured  by  the  flexor 
tendons  at  an  earlier  period  of  the  dissection,  is  now  seen 
arising  from  the  anterior  two  thirds  of  the  metacarpal  bone 
of  the  middle  finger,  on  its  anterior  aspect ;  its  fibres  con- 
verge to  form  a  small  tendon  inserted  into  the  inner  side 
of  the  first  phalanx  of  the  thumb. 

The  radial  artery  enters  the  hand  at  the  first  interosse- 
ous  space,  between  the  two  heads  of  the  abductor  indicis 
muscle.  It  furnishes  a  branch  to  the  thumb,  called  the 
princeps  pollicis;  this  divides  into  two  branches,  which 
pass  along  its  sides  and  inosculate  in  its  pulp ;  another 
branch,  either  from  the  radial  or  from  the  princeps  pollicis, 
supplies  the  radial  side  of  the  forefinger,  and  is  known  as 
the  radialis  indicis;  it  unites  at  the  end  of  the  finger 
with  the  digital  branch  furnished  to  the  opposite  side  by 


PALM     OP    THE    HAND.  155 

the  ulnar  artery.  At  the  anterior  border  of  the  adductor 
pollicis,  the  radialis  indicia  communicates  with  the  superfi- 
cial palmar  arch.  The  continuation  of  the  radial  artery 
is  called  the  deep  palmar  arch  ;  it  extends  across  the  inter- 
osseous  muscles  and  the  metacarpal  bones  to  the  little 
finger,  where  it  anastomoses  with  the  deep  communicating 
branch  of  the  ulnar  artery.  The  arch  sends  off  recurrent 
branches,  which  pass  backward  to  the  carpus,  and  perforat- 
arteries,  which  penetrate  the  interosseous  muscles  to 
>in  the  interosseous  arteries  on  the  back  of  the  hand, 
dually  there  are,  also,, three  palmar  interosseous  arteries 
rich  pass  forward  and  unite  with  the  digital  arteries  of 

superficial  arch  at  the  cleft  of  the  fingers. 
Although  the  distribution  of  the  arteries  of  the  hand, 
lich  has  been  described,  is  the  one  considered  normal,  it 
to  be  remembered  that  "  it  is  not  possible  to  know,  before 
hand  is  opened,  in  what  manner  the  arteries  are  distri- 
ited.m     Sometimes  the  radial   furnishes  the  superficial 
arch,  and  sometimes  there  is  no  arch  at  all ;  the  arrange- 
ment is  extremely  irregular,  and  the  dissector  must  be  pre- 
pared  to   find   a   very   different    arrangement  from  that 
scribed. 

The  deep  branch  of  the  ulnar  nerve  accompanies  the 
leep  palmar  arch  across  the  metacarpal  bones  to  the  mus- 
cles of  the  thumb,  and  terminates  in  branches  to  the  adduc- 
tor pollicis,  the  inner  head  of  the  short  flexor,  and  the 
abductor  indicis. 

The  PALMAR  INTEROSSEOUS  MUSCLES  are  three  in  num- 
ber, and  are  placed  upon,  rather  than  between,  the  meta- 
carpal bones.  The  first  arises  from  the  second  metacarpal 
bone,  and  is  inserted  into  the  ulnar  side  of  the  first  phalanx 
and  extensor  tendon  of  the  forefinger ;  the  second  arises 
from  the  fourth  metacarpal  bone,  and  is  inserted  into  the 
radial  side  of  the  first  phalanx  and  extensor  tendon  of  the 
ring-finger;  the  third  arises  from  the  metacarpal  bone  of 
the  little  finger,  and  is  inserted  into  the  radial  side  of  the 
first  phalanx  and  extensor  tendon  of  the  little  finger. 

The  interosseous  and  lumbricales  muscles  being  sup- 
posed to  convey  to  the  hand  that  peculiar  dexterity  and 
delicacy  of  use  which  is  found  only  in  certain  professions 
or  individuals,  the  dissecting-room  is  not  the  place  to  find 
them  in  their  fullest  degree  of  development. 

1  Horner. 


156        ANATOMY    OF    UPPER    EXTREMITY,    ETC, 


DISSECTION  X. 

LIGAMENTS  OF  THE  RIBS,  SPINE,  AND  UPPER  EXTREMITY. 

To  dissect  the  ligaments,  all  the  fleshy  part  of  muscles  surrounding 
the  joints  must  be  removed  ;  the  tendinous  insertions  are  to  be  left, 
as  in  many  instances  they  enter  largely  into  the  formation  of  the 
articulations  ;  the  cellular  and  all  other  extraneous  tissues  are  to  be 
cleared  away,  so  that  nothing  shall  be  left  to  obscure  the  pearly  aspect 
which  these  parts  present  when  properly  dissected.  Ligatnentous  pre- 
parations are  capable  of  very  brilliant  display,  and,  though  requiring 
much  patience,  are  extremely  interesting  to  make. 

A  piece  of  the  spinal  column,  with  three  or  four  ribs  at- 
tached, furnishes  the  means  of  examining  the  COSTO-VER- 
TEBRAL  and  VERTEBRAL  ARTICULATIONS. 

The  ribs  are  attached  to  the  vertebrae  b}^  two  groups  of 
ligaments ;  one  extending  from  the  head  of  the  rib  to  the 
bodies  of  the  vertebrae,  and  the  other  from  the  tubercle  of 
the  rib  to  the  transverse  processes. 

The  head  of  the  rib,  except  that  of  the  first,  eleventh,  and 
twelfth  ribs,  is  received  in  a  hollow  on  the  sides  of  the 
bodies  of  two  contiguous  vertebrae,  and  is  held  in  place  by 
the  stellate  ligament,  which  passes  from  it  to  the  vertebra  in 
a  radiated  manner,  and  in  those  ribs  connected  with  two 
vertebrae  consists  of  three  distinct  portions,  one  for  the 
superior,  and  one  for  the  inferior  vertebra,  and  a  central 
portion  to  the  inter-vertebral  fibro-cartilage. 

The  inter-articular  ligament  can  only  be  seen  by  a  vertical  section, 
which  shall  include  the  bodies  of  the  contiguous  vertebrae,  and  the 
neck  of  the  rib. 

The  inter-articular  ligament  is  a  short,  thin  band  attached 
on  the  one  side  to  the  ridge  which  separates  the  head  of 
the  rib  into  two  articulating  surfaces,  and  on  the  other,  to 
the  inter-vertebral  fibro-cartilage;  it  divides  the  joint  into 
two  cavities,  each  furnished  with  a  synovial  sac ;  the  first, 
eleventh,  and  twelfth  ribs  have  no  inter-articular  ligament, 
and  consequently  but  one  synovial  sac. 

The  costo-transverse  ligament  extends  from  the  neck  and 
tubercle  of  the  rib  to  the  transverse  process  of  the  ver- 
tebra ;  the  anterior  ascends  from  the  upper  border  of  the 
neck  of  the  rib  to  the  lower  border  of  the  transverse 
process  of  the  upper  of  the  two  vertebrae  with  which  it  is 
connected ;  it  is  necessarily  wanting  in  the  first  rib. 


LIGAMENTS     OF     THE     RIBS,    SPINE,    ETC.         157 

Between  this  ligament  and  the  vertebra,  emerges  the  poste- 
rior branches  of  the  intercostal  artery  and  nerve.  The 
posterior  costo-transverse  ligament  extends  from  the  tuber- 
cle of  the  rib  to  the  tip  of  the  transverse  process. 

The  middle  costo-transverse  ligament  can  only  be  seen  by  a  hori- 
zontal section,  made  through  the  rib  and  transverse  process,  across 
the  vertebra. 

The  middle,  or  interosseous  transverse  ligament,  is  a  very 
strong  band,  passing  directly  between  the  posterior  surface 
of  the  neck  of  the  rib,  and  the  surface  of  the  transverse 
process  against  which  the  rib  rests.  A  synovial  sac  is 
found  between  the  tubercle  of  the  rib  and  the  transverse 
process,  except  in  the  lower  two  ribs,  where  the  tubercles 
and  transverse  processes  do  not  touch. 


The  several  vertebrae  of  the  spinal  column  are  united  by 
ligaments  between  their  bodies  and  processes ;  these  cor- 
respond throughout  the  column,  except  between  the  first 
two  vertebrae  and  the  head ;  these  latter  are  described  at 
p.  74. 

The  anterior  common  ligament  is  a  broad  glistening  band 
which  reaches  the  whole  length  of  the  vertebral  column; 
it  rests  upon  the  front  of  the  bodies  of  the  vertebrae ;  its 
fibres  run  longitudinally,  and  are  widest  opposite  the  lum- 
bar vertebrae. 

The  posterior  common  ligament  lies  upon  the  posterior 
aspect  of  the  bodies  of  the  vertebrae,  within  the  vertebral 
canal,  reaching  from  the  sacrum  to  the  occipital  bone ;  its 
fibres  run  longitudinally,  and  are  in  contact  with  the  dura 
mater ;  it  is  widest  opposite  the  cervical  vertebrae,  and  as 
it  expands  opposite  each  inter-vertebral  disk,  it  has  a  scol- 
loped outline  along  its  borders. 

The  inter-vertebral  substance  is  displayed  by  separating 
two  vertebrae ;  it  lies  between  the  contiguous  surfaces  of 
their  bodies,  in  the  form  of  a  circular  disk,  acting  as  a 
"  buffer"  against  the  shocks  to  which  the  vertebrae  would 
otherwise  be  subject,  and  consists  of  a  firm,  outer,  fibrous 
portion,  the  layers  of  which  are  concentrically  arranged, 
and  of  a  soft  and  elastic  central  portion,  which  bulges 
when  two  vertebrae  are  cut  apart,  or  sawn  through  longi- 
tudinally. By  separating  the  inter-vertebral  substance 
14 


158        ANATOMY     OF     UPPER     EXTREMITY,    ETC. 

from  the  bone,  it  will  be  found  that  the  vertebra  has  a 
cartilaginous  covering  between  it  and  the  disk. 

The  processes  of  the  vertebrae  have  special  uniting  liga- 
ments. 

The  ligamenta  subflava  are  elastic  layers  placed  between 
the  arches  of  the  vertebrae,  stretching  from  the  lower 
border  of  one  to  the  upper  border  of  the  next ;  they  are 
longest  in  the  cervical  region. 

The  supra-spinous  ligament  extends  along  the  tips  of 
the  spinous  processes,  and  is  best  developed  in  the  lumbar 
region. 

The  inter-spinous  ligaments  lie  between  the  upper  and 
lower  borders  of  the  spinous  processes,  and  extend  from 
the  root  to  the  tip  of  the  process ;  they  are  best  marked 
in  the  lumbar  region. 

The  inter-transverse  ligaments  extend  between  the  trans- 
verse processes,  as  thin  bands  in  the  lumbar,  and  as  round 
bundles  in  the  dorsal  vertebrae ;  they  are  wanting  in  the 
cervical  region. 

A  capsular  ligament,  not  very  well  marked,  surrounds 
the  articular  processes,  and  incloses  a  sy  no  vial  membrane. 


The  clavicle  is  united  to  the  scapula  by  an  articulation 
with  the  acromion,  and  by  a  ligament  between  the  clavicle 
and  the  coracoid  process. 

The  ACROMIO-CLAVICULAR  ARTICULATION  is  maintained 
by  scattered  fibres,  which  make  a  kind  of  capsule  for  the 
joint ;  an  inter-articular  fibro-cartilage,  often  indistinct, 
exists  between  the  two  bones,  and  a  synovial  membrane 
lines  the  interior  of  the  articulations. 

The  coraco-clavicular  ligament  is  a  thick  fasciculus, 
reaching  from  the  base  of  the  coracoid  process  to  the 
under  surface  of  the  clavicle;  when  seen  from  the  front,  its 
fibres  present  a  quadrilateral  shape,  and  it  is  hence  called 
the  trapezoid  ligament ;  when  seen  from  behind,  it  is  tri- 
angular in  shape,  and  is  then  called  the  conoid  ligament. 

The  scapula  has  two  ligaments  unconnected  with  any 
other  bone ;  the  coraco-acromial,  and  the  transverse. 

The  coraco-acromial  ligament  is  triangular  in  shape,  and 
extends  transversely  between  the  coracoid  process  and  the 
acromion,  its  apex  being  attached  to  the  end  of  the  acro- 
mion, and  its  wider  base  into  the  whole  length  of  the  cora- 
coid process. 


LIGAMENTS    OF    THE    ELBOW-JOINT.  159 

The  transverse  ligament  converts  the  notch  in  the  upper 
border  of  the  scapula  into  a  foramen. 

A  capsular  ligament  incloses  the  SHOULDER  JOINT.  It  is 
attached  above,  to  the  neck  of  the  scapula,  and  below,  to 
the  humerus,  close  to  its  articular  surface ;  internally  it  is 
lined  with  a  synovial  membrane  ;  it  is  strengthened  by  the 
tendons  of  the  muscles  of  the  scapula,  and  by  a  broad  band, 
called  the  coraco-humeral  ligament,  which  extends  from  the 
base  of  the  coracoid  process  to  the  greater  tuberosity  of 
the  humerus.  The  long  tendon  of  the  biceps  muscle  pene- 
trates the  capsule  between  the  tuberosities  of  the  humerus, 
and  is  attached  to  the  upper  part  of  the  glenoid  fossa  of 
the  scapula;  this  tendon  is  surrounded  by  a  prolongation 
of  the  capsular  synovial  membrane. 

The  glenoid  ligament  consists  of  a  fibrous  band,  con- 
tinuous with  the  tendon  of  the  biceps,  from  which  it  seems 
to  be  formed,  and  which  surrounds  and  deepens  the  glenoid 
fossa  of  the  scapula. 


The  bones  of  the  ELBOW- JOINT  are  kept  in  place  by  the 
following  ligaments : — 

The  external  lateral  ligament  consists  of  a  round  fascicu- 
lus attached  to  the  external  condyle  above,  and  the  orbicu- 
lar ligament  of  the  radius  below. 

The  internal  lateral  ligament,  triangular  in  shape,  is  at- 
tached above,  by  its  apex,  to  the  internal  condyle,  and 
below,  by  its  base,  to  the  margin  of  the  sigmoid  notch  of 
the  ulna,  from  the  coronoid  process  to  the  olecranon. 

When  the  supra-condyloid  process  is  present,  a  ligament 
extends  from  its  tip  to  the  internal  condyle,  thus  com- 
pleting the  analogy  it  is  supposed  to  have  with  the  foramen 
in  the  lower  part  of  the  humerus,  through  which  the  bra- 
chial  artery  passes  in  certain  classes  of  animals. 

The  anterior  ligament  extends  from  the  front  of  the 
humerus  to  the  coronoid  process  and  orbicular  ligament ; 
its  fibres  are  very  thin  and  pass  in  various  directions. 

The  posterior  ligament  is  attached  superiorly  to  the 
humerus,  above  the  fossa  for  the  olecranon,  and  inferiorl}r 
to  the  edges  of  the  olecranon  process. 

The  radius  is  held  to  the  ulna  by  the  orbicular  ligament, 
a  broad  band  which  surrounds  its  head,  and  is  inserted  by 
its  two  extremities  at  either  end  of  the  lesser  sigmoid  notch 
of  the  ulna. 


160        ANATOMY     OF     UPPER     EXTREMITY,    ETC. 

The  oblique  ligament  is  a  slender  band,  sometimes  wam 
ing,  which  extends  from  the  front  of  the  coronoicl  process 
to  the  radius  below  its  tubercle. 

The  tendon  of  insertion  of  the  biceps  muscle  may  now  be 
examined  better  than  could  be  done  previously  ;  a  bursa  is 
found  between  it  and  the  bone ;  near  its  attachment  the 
tendon  twists,  its  anterior  surface  becoming  external,  and 
vice  versa. 

The  interosseous  membrane  is  a  thin  fibrous  la}^er,  at- 
tached to  the  contiguous  margins  of  the  radius  and  ulna, 
separating  the  muscles  of  the  front  and  back  part  of 
the  forearm  ;  its  fibres  are  directed  obliquely  downward 
toward  the  ulna ;  superiorly  the  membrane  is  wanting. 


The  WRIST-JOINT  is  maintained  by  four  ligaments  : — 

The  external  lateral  ligament  is  a  short  strong  band  be- 
tween the  stj^loid  process  of  the  radius  and  the  upper  part 
of  the  scaphoid  bone. 

The  internal  lateral  ligament  is  smaller  but  longer  than 
the  external ;  it  extends  between  the  styloid  process  of  the 
ulna  and  the  upper  part  of  the  cuneiform  bone. 

The  anterior  ligament  is  a  membranous  layer  reaching 
from  the  end  of  the  radius  to  the  anterior  surface  of  the 
first  row  of  carpal  bones. 

The  posterior  ligament  is  also  a  membranous  layer,  and 
extends  from  the  lower  end  of  the  radius  to  the  posterior 
aspect  of  the  first  row  of  carpal  bones. 

The  radius  and  ulna  are  held  together  at  their  lower  arti- 
culation by  a  triangular  fibro-cartilage,  placed  between 
them  ;  this  is  attached  b}'  its  apex  to  the  inner  surface  of 
the  styloid  process  of  the  ulna,  and  by  its  base  to  the  edge 
of  the  lesser  articulating  surface  of  the  radius ;  a  few  scat- 
tered fibres  loosely  surround  this  joint  by  way  of  a  capsular 
ligament. 

The  carpal  bones  are  united  into  two  rows  by  dorsal,  pal- 
mar, and  interosseous  bands,  and  the  two  rows  are  simi- 
larly united  with  each  other;  they  are  all  supplied  by  one 
sy  no  vial  membrane,  except  the  pisiform  bone,  which  has  a 
capsule  and  synovial  membrane  distinct  from  the  others ; 
it  has  also  two  special  ligaments,  one  to  the  process  of  the 
imciform  bone  and  the  other  to  the  base  of  the  fifth  meta- 
carpal  bone. 


LIGAMENTS     OF     THE     FINGERS.  161 

The  CARPO-METACARPAL  ARTICULATIONS  are  maintained 
.by  dorsal  and  palmar  ligaments,  excepting  in  the  thumb, 
which  has  a  capsular  ligament  connecting  it  with  the  tra- 
pezium. 

The  metacarpal  bones  are  united  at  their  bases  by  trans- 
verse dorsal,  and  palmar  ligaments,  and  by  interosseous 
ligaments,  which  pass  between  their  contiguous  surfaces ; 
these  may  be  demonstrated  by  tearing  the  bones  apart  when 

Ee  dissection  is  completed. 
The  METACARPO-PHALANGEAL  ARTICULATIONS  are  main- 
ined  by  anterior  and  lateral  ligaments,  and  by  transverse 
laments,  which  hold  together  the  heads  of  the  metacarpal 
>nes  of  the  four  fingers.   The  extensor  tendon  of  the  finger 
kes  the  place  of  a  posterior  ligament. 
The  PHALANGEAL  ARTICULATIONS  have  three  ligaments  ; 
the  anterior,  firm  and  fibre-cartilaginous,  and  grooved  for 
the  flexor  tendons ;  the  lateral  ligaments,  one  on  each  side, 
triangular  in  form,  the  apex  being  attached  to  the  pha- 
lanx in  front,  and  the  base  to  the  tubercle  at  the  side  of  the 
phalanx  behind.     The  extensor  tendons  supply  the  place  of 
posterior  ligaments. 


14* 


PAET    THIRD. 

ANATOMY  OF  THE  ABDOMEN  AND  LOWER 
EXTREMITY. 

DISSECTION  I. 

PARIETES    OF    THE  ABDOMEN. 

A  block  is  to  be  placed  under  the  lumbar  vertebrae,  and  the  abdo- 
minal muscles  made  tense  by  inflating  the  peritoneal  cavity  by  a  blow- 
pipe introduced  through  the  umbilicus.  A  longitudinal  incision  is  to  be 
made  from  the  ensiform  cartilage  to  the  pubes,  penetrating  to  the  ten- 
dons of  the  muscles  ;  the  amount  of  fat  to  be  divided  varies  so  much 
that  great  caution  is  necessary  lest  the  tendons  themselves  be  wound- 
ed ;  when  reached  they  are  known  by  their  white  and  glistening 
aspect.  From  just  below  the  umbilicus  a  second  incision  is  to  be  car- 
ried upward  and  outward  to  the  most  dependent  part  of  the  margin 
of  the  thorax.  The  precaution  above  mentioned  must  also  be  ob- 
served in  the  inner  half  of  this  incision,  which  posteriorly  should 
penetrate  to  the  muscular  fibres.  The  two  angular  flaps  of  integu- 
ment thus  formed  are  to  be  reflected  upward  and  downward.  The  dis- 
sector must  keep  close  to  the  tendon,  cleaning  it  carefully  and  slowly 
from  all  the  cellular  tissue  and  superjacent  parts,  and,  when  dissecting 
the  muscular  portion,  follow  the  direction  of  its  fibres,  freeing  them 
patiently,  one  by  one,  from  their  sheath,  being  particularly  careful  at 
the  point  of  their  junction  with  the  broad  flat  tendon  into  which  they 
are  inserted,  not  to  divide  and  dissect  up  the  tendon  itself,  but  to  keep 
it  intact  in  its  whole  extent.  Toward  the  groin  more  or  less  of  the 
fascia  should  be  left,  in  order  to  observe  its  relations  to  the  external 
abdominal  ring.  The  external  oblique  muscle  cannot  be  exposed 
posteriorly  without  turning  the  subject  over  upon  its  face,  or  at  least 
upon  its  side.  The  abdominal  muscles  are  almost  invariably  disco- 
lored of  a  greenish  hue  ;  this  is  not  usually  owing  to  decomposition, 
but  to  the  effect  of  sulphuretted  hydrogen  in  the  intestinal  canal  upon 
the  coloring  matter  of  the  blood  in  the  muscular  tissue. 

The  PARIETES  OF  THE  ABDOMEN  extend  from  the  median 
line  to  the  spinal  column  on  each  side,  and  from  the  ribs 
above  to  the  pelvis  below ;  they  include  three  pairs  of  flat 
muscles,  disposed  in  layers,  and  the  direction  of  whose 
fibres  is  different ;  in  front  they  terminate  in  extensive  apo- 
neuroses,  also  disposed  in  layers,  and  between  them  on 


PARIETES    OF    THE    ABDOMEN.  163 

each  side  of  the  median  line  extends  a  single  long  muscle. 
The  abdomen  is  covered  by  a  fascia  and  a  very  variable 
amount  of  fat. 

The  superficial  fascia  is  continuous  with  that  of  the 
thorax  and  lower  extremity.  ]STo  special  dissection  of  it  is 
necessary.  It  is  only  important  in  the  inguinal  region, 
where  it  divides  into  two  Ia3^ers,  and,  as  will  hereafter  be 
seen,  bears  certain  relations  to  the  surgical  affection  called 
hernia ;  these  two  layers  are  separated  by  the  superficial 
epigastric  artery  and  vein,  the  former  being  a  small  branch 
from  the  femoral,  arising  below  Pou part's  ligament,  and 
passing  upward  toward  the  umbilicus.  It  will  be  seen  that 
certain  fibres  of  the  superficial  fascia  pass  from  the  pubes 
to  the  penis,  forming  a  rounded  cord  called  the  ligamentum 
suspensorium  penis.  In  the  groin  the  fascia  attaches  itself 
to  Poupart's  ligament,  and  through  that  becomes  blended 
with  the  fascia  of  the  thigh ;  it  covers  the  spermatic  cord, 
and,  accompanying  it  to  the  scrotum,  there  unites  with  the 
fascia  of  the  perineum.  Between  its  two  layers,  and  above 
Poupart's  ligament,  three  or  four  lymphatic  glands  will  be 
found ;  these  receive  the  lymphatics  from  the  abdomen  and 
genital  organs,  and  their  efferent  ducts  pass  in  at  the 
saphenons  opening  of  the  thigh. 

The  OBLIQUUS  EXTERNUS  MUSCLE  is  the  most  superficial 
of  the  abdominal  muscles ;  it  is  aponeurotic  in  front  and 
fleshy  upon  the  side ;  it  arises  from  the  external  surface  of 
eight  or  nine  lower  ribs  by  processes  called  digitations, 
which  are  received  between  similar  processes  belonging  to 
the  serratus  magnus  and  latissimus  dorsi.  It  is  inserted  into 
the  outer  edge  of  the  anterior  half  of  the  crest  of  the  ilium 
and  its  anterior  superior  spinous  process,  into  the  spine, 
pectineal  line  and  front  of  the  os  pubis,  and  into  the  whole 
length  of  the  linea  alba.  The  portion  inserted  into  the  crest 
of  the  ilium  is  fleshy  ;  the  remainder  consists  of  a  spread- 
ing aponeurosis,  connected  above  with  the  pectoralis  major 
muscle,  and  along  the  median  line  uniting  with  its  fellow 
of  the  other  side ;  the  interlacement  of  their  fibres  forms 
what  is  called  the  linea  alba,  in  the  centre  of  which  is  the 
umbilicus,  being  the  cicatrix  of  the  occluded  extremities  of 
the  umbilical  artery  and  vein  which  composed  the  umbilical 
cord,  divided  at  the  time  of  birth,  and  the  stump  of  which 
subsequently  sloughs  off.  Between  the  anterior  superior 
spinous  process  of  the  ilium  and  the  spine  of  the  pubes 
the  fibres  of  the  external  oblique  become  rolled  into  a  sort 


164  ANATOMY     OF     THE     ABDOMEN,    ETC. 

of  cord,  known  as  Pouparfs  ligament,  and  which  is  con- 
tinuous by  its  lower  border  with  the  fascia  lata  of  the 
thigh.  When  properly  dissected,  small  foramina  will  be 
noticed  in  the  aponeurosis,  giving  exit  to  the  cutaneous 
nerves  and  vessels ;  the  nerves  are  branches  of  the  inter- 
costals,  and  of  the  lumbar  plexus,  and  the  arteries  are 
chiefly  from  the  internal  mammary,  lumbar,  and  circum- 
flexa  ilii.  The  outline  of  the  rectus  muscle  can  be  plainly 
seen  through  the  tendon  of  the  external  oblique;  the  curved 
line  which  indicates  its  external  border  and  extends  from 
the  os  pubes  to  the  chest  is  called  the  linea  arcuata.  At 
the  pubes  the  fibres  of  the  aponeurosis  split,  and  leave  a 
space  which  affords  passage  to  the  spermatic  cord  in  the 
mals  and  the  round  ligament  in  the  female :  this  space  is 
very  variable  in  size,  and  is  usually  larger  in  the  male  than 
the  female  subject ;  although  there  is  nothing  annular  in 
its  conformation  to  give  it  such  a  name,  it  is  called  the 
external  abdominal  ring.  The  fibres  forming  its  superior 
border  or  pillar  interlace  with  those  of  the  opposite  side 
in  front  of  the  symphysis  pubes ;  its  inferior  border  or 
pillar  is  formed  from  the  internal  portion  of  Poupart's 
ligament.  Just  above  the  spermatic  cord  this  separation 
in  the  aponeurosis  is  traversed  by  a  series  of  transverse 
fibres,  variable  both  in  size  and  number ;  they  extend  for  a 
considerable  distance  on  either  side  of  the  pillars,  and 
constitute  what  are  called  the  inter-columnar  fibres.  Be- 
tween the  pillars,  covering  in  the  cord  and  prolonged  upon 
it,  is  a  thin  and  delicate  expansion  called  the  spermatic 
fascia;  if  this  is  divided  transversely  upon  the  cord,  the 
handle  of  the  scalpel  may  be  passed  under  it  and  pushed 
upward  beneath  the  tendon ;  this  will  demonstrate  its  ex- 
istence as  a  layer  distinct  from  the  elements  of  the  cord. 

The  external  oblique  is  to  be  removed  by  dividing  it  transversely 
across  its  fleshy  part  ;  the  change  in  the  direction  of  the  fibres  will 
show  when  the  internal  oblique  is  reached.  In  accomplishing  the 
Reparation  of  these  two  muscles,  the  fascia  of  the  internal  muscle 
should  be  removed  with  the  external.  In  order  to  reserve  the  in- 
guinal region,  the  tendon  should  be  divided  transversely  from  the 
anterior  superior  spinous  process  to  the  linea  alba,  and  down  the  linea 
alba  to  near  the  pubes,  so  far  as  the  close  union  with  the  muscle 
beneath  will  permit,  the  portion  below  being  left  for  further  examina- 
tion. The  obliquus  internus  is  thus  exposed,  except  at  its  lower 
part,  which,  by  a  little  manipulation,  may  also  be  seen,  on  turning 
downward  that  portion  of  the  external  oblique  which  has  been  left 
attached. 


ii 

: 


PARIETES    OP    THE    ABDOMEN.  165 

The  OBLIQUUS  INTERNUS  MUSCLE  arises  from  the  outer 
half  of  Ponpart's  ligament,  from  the  anterior  two-thirds  of 
the  crest  of  the  iliuin,  and  from  that  portion  of  the  lumbar 
fascia  which  is  attached  to  the  spinous  processes  of  the 
lumbar  vertebrae.  The  fibres  of  the  lower  part  of  this  mus- 
cle are  thin,  and  separated  from  each  other ;  they  curve 
over  the  spermatic  cord,  or  round  ligament,  and  uniting 
with  the  tendon  of  the  muscle  beneath,  under  the  name  of 
the  conjoined  tendon  of  the  internal  oblique  and  trans- 
versalis  muscles,  are  inserted  into  the  crest  of  the  pubes 
and  the  pectineal  line  behind  the  tendon  of  the  external 
oblique.  The  remainder  of  the  fibres  pass  upward  and 
inward,  and  terminate  in  an  aponeurosis  at  the  outer 
order  of  the  rectus  muscle.  The  upper  half  of  this 
poneurosis  splits  into  two  laminae,  which  encase  the 
pper  half  of  that  muscle,  and  meet  on  the  median  line  ; 
the  whole  of  the  aponeurosis  passes  in  front  of  the  lower 
half  of  the  muscle,  blending  with  the  tendon  of  the  ex- 
ternal oblique.  Along  the  linea  alba,  the  tendons  of  the 
two  sides  unite  inseparably.  Superiorly  the  muscle  is  in- 
serted into  the  lower  border  of  the  cartilages  of  the  last 
four  ribs. 

In  arching  over  the  spermatic  cord,  certain  of  the  muscu- 
lar fibres  are  prolonged,  and  carried  downward,  in  long 
loops,  by  the  testicles  at  the  period  of  their  descent ;  these 
fibres  may  be  seen  as  a  muscular  layer  upon  the  cord,  and 
are  called  the  cremaster  muscle  ;  they  vary  very  much  in 
distinctness,  and  do  not  exist  in  the  female  subject.  They 
are  sometimes  described  as  coming  from  the  transversalis 
muscle,  as  well  as  the  internal  oblique,  the  two  muscles 
being  intimately  blended  at  this  point. 

The  separation  of  this  muscle  from  the  next  is  with  difficulty 
accomplished  in  a  manner  which  leaves  the  transversalis  neatly  and 
fairly  exposed.  The  fibres  of  the  internal  oblique  should  be  divided 
transversely  to  their  direction  ;  the  different  direction  of  its  fibres  and 
the  ramifications  of  vessels  in  the  space  between  the  muscles,  will  tell 
when  the  transversalis  is  reached  ;  the  internal  oblique  is  to  be  dis- 
sected away  from  it,  and  divided  from  its  own  tendon  along  the  outer 
edge  of  the  rectus  muscle.  The  lower  fibres,  which  assume  a  similar 
direction  to  those  of  the  transversalis,  and  to  a  certain  extent  become 
confounded  with  them,  may  be  left  behind,  with  reference  to  a  more 
special  examination  of  the  inguinal  region  in  relation  to  hernia. 

The  TRANSVERSALIS  MUSCLE  arises  from  the  outer  half 
of  Poupart's  ligament,  from  the  anterior  three-fourths  of 


166      ANATOMY  OF  THE  ABDOMEN,  ETC. 

the  inner  lip  of  the  crest  of  the  ilium,  from  the  lumbar 
fascia,  i.  e.,  from  the  spiiioiis  processes  and  the  tips  and 
bases  of  the  transverse  processes  of  the  lumbar  vertebras, 
and  from  the  under  surface  of  the  last  six  or  seven  ribs, 
where  it  indigitates  with  the  diaphragm.  Its  fibres  pass 
transversely  forward,  and  terminate  in  an  aponeurosis,  the 
upper  two-thirds  of  which  passes  behind,  and  the  lower 
third  in  front  of  the  rectus  muscle,  to  be  inserted  into  the 
linea  alba.  The  lower  fibres  of  the  muscle  cover  over  the 
spermatic  cord,  or  round  ligament,  and  are  inserted  into 
the  pectineal  line,  in  connection  with  the  lower  fibres  of  the 
internal  oblique,  under  the  name  of  the  conjoined  tendon ; 
these  lower  fibres  are  few  in  number,  and  separated  from 
each  other ;  indeed,  the  portion  arising  from  Poupart's 
ligament  is  sometimes  deficient,  and  at  others  confounded 
with,  and  inseparable  from,  the  internal  oblique ;  in  either 
case  the  transversalis  fascia  and  peritoneum  maybe  seen 
through  the  fibres :  the  internal  oblique  usually  descends 
nearest  to  Poupart's  ligament,  while  the  transversalis 
makes  up  the  greater  part  of  the  conjoined  tendon.  The 
circumflexa  ilii  artery,  a  branch  of  the  external  iliac,  and 
the  musculo-cutaneous  nerve  from  the  lumbar  plexus, 
ramify  upon  and  in  this  muscle  above  the  crest  of  the  ilium. 

The  rectus  muscle  is  exposed  by  dividing  the  aponeurosis  which 
covers  it  in  front,  from  the  sternum  to  the  pubes,  at  about  an  inch 
from  the  median  line  ;  at  two  or  three  points  this  sheath  will  be 
found  adherent  to  certain  tendinous  intersections  which  traverse  the 
muscle  ;  the  aponeurosis  should  be  carefully  dissected  from  them. 

The  RECTUS  MUSCLE,  broad  above  and  narrow  below, 
arises  by  a  thick  tendon  from  the  crest  of  the  os  pubis ; 
becoming  thinner  as  it  grows  broader,  it  is  inserted  into 
the  cartilages  of  the  fifth,  sixth,  and  seventh  ribs ;  it  is 
separated  from  its  fellow  by  an  interval,  formed  by  the 
aggregation  of  the  fibres  of  the  tendons  of  the  abdominal 
muscles  of  the  two  sides,  which  constitutes  the  linea  alba. 
Two  or  three  tendinous  intersections,  sometimes  complete, 
at  others  only  partial,  cross  the  rectus  in  irregular  direc- 
tions ;  they  are  called  linese  transversae,  and  serve  to  keep 
the  muscle  flat  during  its  contractions,  since  without  them, 
its  broad  insertion  and  narrow  origin  would  give  it  a  tend- 
ency to  roll  into  a  cone  longitudinally.  The  rectus  mus- 
cle is  occasionally  inserted  as  high  as  the  fourth,  or  even 
third  rib.  Sometimes  there  may  be  found  an  abnormal 


PARIETES    OF    THE    ABDOMEN.  16t 

muscle  upon  the  sternum,  which  appears,  physiologically 
at  least,  to  be  a  continuation  of  this  muscle  ;  it  is  called 
the  rectus  sternalis,  and  is  described  as  being  occasionally 
connected  with  the  sterno-mastoid,  instances  being  re- 
corded where  the  sterno-mastoid  and  rectns  were  one  con- 
tinuous muscle.  This  occasional  slip,  and  the  high  inser- 
tion of  the  rectus,  is  looked  upon  as  corresponding  with 
the  long  rectus  of  the  lower  orders  of  animals. 

The  PYRAMIDALIS  MUSCLE,  small  and  triangular  in  shape, 
lies  upon  and  inclosed  within  the  sheath  of  the  rectus,  and 
is,  as  it  were,  accessory  to  that  muscle,  which  becomes 
nlarged  at  its  lower  part  when  it  is  absent ;  it  arises  from 
e  crest  of  the  os  pubis,  and,  tapering  as  it  goes  upward, 
inserted  into  the  linea  alba  from  two  to  four  inches  above 
e   s}rmph3Tsis   pubes.      This   muscle   is   very  commonly 
ting  on  one  or  both  sides. 

The  rectus  muscle  should  be  divided  at  the  umbilicus ;  the  two 
ends  will  be  easily  dissected  up  from  their  posterior  cellular  attach- 
ments, and  it  will  then  be  seen  how  it  is  encased  by  the  aponeurosis 
of  the  abdominal  muscles. 

In  front  of  the  upper  half  of  the  rectus  muscle  expands 
the  aponeurotic  tendon  of  the  external  oblique,  and  the 
anterior  layer  of  that  of  the  internal  oblique ;  behind  the 
upper  half  are  the  posterior  layer  of  the  tendon  of  the 
internal  oblique,  and  the  whole  of  that  of  the  transversalis. 
Below  the  umbilicus  all  the  tendons  pass  in  front,  while 
behind,  the  rectus  is  separated  from  the  viscera  only  by  the 
transversalis  fascia  and  the  peritoneum.  The  lower  edge 
of  the  tendons  forming  the  posterior  sheath  of  the  upper 
half  of  the  rectus  muscle  assumes  a  crescentic  shape,  and 
is  called  the  semilunar  fold  of  Douglass;  the  space  below 
this  fold,  between  the  peritoneum  and  the  muscle,  Retzius 
has  described  as  a  " pre-peritoneal  cavity,"  having  proper 
walls,  formed  by  the  transversalis  fascia,  and  destined  to 
accommodate  the  bladder  in  its  changes  of  volume,  and 
enabling  the  recti  muscles  to  act  more  directly  upon  that 
viscus  in  emptying  it  of  its  contents.  Below  the  umbilicus 
the  linea  alba  becomes  more  tendinous  than  above  that 
point,  and  the  peritoneum  is  manifestly  less  closely  con- 
nected with  the  abdominal  walls.  The  epigastric  artery,  a 
branch  of  the  external  iliac,  will  be  seen  penetrating  the 
lower  half  Of  the  rectus,  and  lying  loose  between  it  and  its 
sheath  for  a  portion  of  its  course;  if  well  injected,  it  may 


168  ANATOMY     OF    THE    ABDOMEN,    ETC. 

also  be  traced  in  the  fibres  of  the  muscle  to  an  anastomosis 
with  the  terminal  branches  of  the  internal  mammary  artery. 
It  was  by  the  aid  of  these  anastomoses  that  some  of  the 
old  anatomists  endeavored  to  explain  the  intimate  relation- 
ship between  the  genital  organs  and  the  mammary  gland. 
At  the  lower  part  of  the  inner  surface  of  the  rectus  muscle 
will  be  seen  a  thin  layer  of  diverging  fibres,  springing  from 
the  insertion  of  Poupart's  ligament  into  the  pectineal  line, 
and  ascending  upward  and  inward  to  the  linea  alba  in  which 
they  are  lost;  it  is  called  the  triangular  ligament. 

ANATOMY    OF    INGUINAL    HERNIA. 

It  is  always  desirable,  if  possible,  to  make  a  special  dissection  of 
the  inguinal  region  ;  but  if  the  student  has  left  the  lower  part  of  the 
abdominal  muscles  as  directed,  it  may  be  very  satisfactorily  examined 
after  the  general  dissection  is  accomplished.  The  dissection  can  be 
advantageously  performed  only  upon  the  male  subject. 

Under  the  influence  of  violent  exertions,  and  sometimes 
passive!}',  a  portion  of  the  contents  of  the  abdomen  may 
be  protruded  at  such  parts  of  its  walls,  as,  from  their  con- 
formation, are  weaker  or  less  protected  than  others.  This 
protrusion  is  called  hernia,  or  rupture.  The  inguinal  region 
is  a  point  at  which  it  frequently  occurs.  To  understand 
why  this  region  is  liable  to  this  accident,  it  is  necessary  to 
examine  it  specially  in  this  relation. 

The  INGUINAL  REGION  is  included  between  Poupart's  liga- 
ment, the  linea  alba,  and  an  imaginary  transverse  line  from 
the  latter  to  the  anterior  superior  spinous  process  of  the 
ilium ;  most  of  its  parts  have  already  been  separately 
described.  The  perforation  of  the  external  oblique  by  the 
spermatic  cord,  the  thinness,  or  partial  deficiency  of  the 
fibres  of  the  internal  oblique  and  trans versalis  muscles, 
make  it  apparent  that  less  resistance  would  be  offered  here 
than  elsewhere  to  the  superincumbent  weight  of  the  abdo- 
minal viscera,  and  that  their  impulsion  against  it,  during 
efforts  which  contracted  the  diaphragm  and  abdominnl 
muscles,  would  render  protrusion  of  the  intestines  or 
omentum  at  this  point  a  very  conceivable  occurrence. 

The  superficial  fascia,  but  for  its  relation  to  the  anatomy 
of  hernia,  would  be  considered  merely  as  the  sheath  of  the 
external  oblique,  in  which  a  certain  amount  of  fat  was 
deposited.  It  is  usually  spoken  of  as  consisting  of  two 
layers,  separated  by  the  superficial  epigastric  artery  and 
vein.  Unless  a  special  dissection  of  it  has  been  made,  it 


ANATOMY    OF    INGUINAL    HERNIA.  169 

will  probably  be  found  that  one  of  these  layers  has  been 
removed  with  the  skin.  Directly  beneath  this  is  the  ten- 
don of  the  external  oblique,  between  the  fibres  of  which 
emerges  the  spermatic  cord.  This  point  of  emergence  is 
called  the  external  abdominal  ring,  and  consists  merely  of 
a  separation  of  the  tendon,  the  upper  border  of  which  is 
called  the  superior  pillar,  and  the  lower,  the  inferior  pillar 
of  the  ring.  The  further  separation  of  these  pillars  is 
prevented  by  transverse  fibres,  called  inter-columnar.  The 
spermatic  cord  consists  of  the  excretor}^  duct  of  the  testi- 
cle, called  the  vas  deferens,  the  spermatic  artery  and  vein, 
a  nerve,  some  lymphatics,  and  cellular  tissue.  These  con- 
stitute a  bundle  of  considerable  size,  reinforced  by  the 
cremaster  muscle,  which  is  not  properly  a  part  of  the  cord, 
the  whole  of  which  lies  behind  a  thin  fascia,  extending 
across  the  pillars  of  the  external  ring,  and  continued  down 
upon  the  cord,  called  the  spermatic  fascia. 

Upon  reflecting  the  lower  part  of  the  external  oblique, 
toward  the  groin,  the  spermatic  cord  will  be  observed  lying 
for  a  short  distance  behind  it ;  the  internal  oblique  and 
transversalis  curve  over  it,  and  Poupart's  ligament  is 
directly  beneath  it.  The  cremaster  muscle,  being  fibres  of 
the  internal  oblique  and  transversalis  muscles,  lies  upon 
the  cord  itself,  and  its  connection  with  those  muscles  may 
possibly  be  traced.  The  space  traversed  by  the  cord,  be- 
hind the  external  oblique,  is  called  the  inguinal  canal. 

If  the  internal  oblique  and  transversalis  are  separated, 
upon  turning  down  the  lower  part  of  the  former  muscle, 
it  will  be  seen  that  the  transversalis  leaves  a  space  between 
itself  and  Poupart's  ligament ;  in  this  space  will  be  seen 
the  transversalis  fascia,  and  upon  reflecting  the  transver- 
salis muscle,  it  will  be  seen  lying  behind  it,  upon  the  peri- 
toneum. This,  like  the  superficial  fascia,  were  it  not  for 
its  relations  to  hernia,  would  be  considered  merely  as  the 
sheath  of  the  transversalis  muscle ;  it  is  of  very  variable 
thickness,  sometimes  amounting  to  nothing  but  a  little 
cellular  tissue;  it  is  attached  to  Poupart's  ligament  below, 
and  internally  to  the  conjoined  tendon  and  sheath  of  the 
rectus  muscle.  By  pulling  the  spermatic  cord,  it  will  be 
seen  that  this  fascia  is  reflected  from  the  peritoneum  on  to 
the  surface  of  the  cord,  and  the  cone  which  is  thus  formed 
and  made  apparent,  by  this  traction,  is  called  the  infundi- 
buliform  fascia.  The  orifice  forming  the  base  of  this  cone, 
and  across  which  the  peritoneum  is  stretched,  is  the  inter- 
15 


170      ANATOMY  OF  THE  ABDOMEN,  ETC. 

nal  abdominal  ring.  By  incising  the  fascia  on  the  peri- 
toneum, the  handle  of  a  scalpel  may  be  inserted,  and 
pushed  down  the  cord  between  it  and  that  portion  of  the 
transversalis  fascia  just  described  as  the  infundibuliform, 
showing  that  at  this  point  the  peritoneum  might  be  pro- 
truded before  a  knuckle  of  intestine,  and,  if  forced  onward, 
must  pass  down  in  the  direction  taken  by  the  knife-handle, 
between  the  fascia  and  the  cord.  The  epigastric  artery 
lies  between  the  transversalis  fascia  and  the  peritoneum ;  it 
passes  under  the  cord  close  to  the  inguinal  ring ;  the  vas 
deferens  hooks  over  it  as  it  turns  downward  into  the  pelvis. 

A  large  triangular  flap  of  the  peritoneum  being  incised 
and  turned  toward  the  groin,  it  will  be  noticed  that,  upon 
the  median  line,  there  is  a  cord  passing  from  the  bladder 
'to  the  linea  alba ;  this  is  the  remains  of  the  allantois  of 
foetal  life ;  another  cord,  being  the  remains  of  the  oblite- 
rated hypogastric  artery  of  foetal  life,  passes  obliquely 
from  the  umbilicus  downward  toward  the  pelvis,  in  a  line 
nearty  corresponding  to  that  of  the  epigastric  artery :  this 
cord,  by  its  shortness,  causes  the  peritoneum  to  make  a 
pouch  on  each  side — these  are  called  the  inguinal  fossae  ; 
one  of  them  is  behind  the  external  ring,  and  the  other 
behind  the  internal  ring,  and  it  will  be  seen  that  each  must 
direct  that  portion  of  intestine  which  accidentally  lies  within 
it  toward  the  ring  that  lies  in  front  of  it,  and  as  the  abdo- 
minal wall  corresponding  to  the  external  ring  is  weaker 
than  elsewhere,  owing  to  the  loss,  at  that  point,  of  one  of 
the  layers  constituting  its  thickness,  and  at  the  internal 
ring,  owing  to  the  conformation  already  described,  it  fol- 
lows that  a  hernia  is  liable  to  occur  at  either  situation ;  it 
.  is  called  a  direct  hernia,  if  it  protrudes  from  directly  oppo- 
site the  external  ring,  and  an  oblique  hernia,  if  it  enters 
the  internal  ring,  and  follows  the  direction  of  the  sperma- 
tic cord. 

By  pulling  upon  the  spermatic  cord,  the  peritoneum  will 
exhibit,  at  the  part  affected  by  the  traction,  a  puckered 
appearance ;  this  is  the  point  at  which  that  point  of  the 
peritoneum,  carried  before  the  testicle  in  its  descent  to  the 
scrotum,  is  obliterated  from  its  connection  with  the  general 
cavity.  The  portion  of  peritoneum  intervening  between 
this  point  and  the  scrotum,  usually  degenerates  into  cellu- 
lar tissue ;  it  ma}^,  however,  remain  as  a  distinct  cord,  or 
even  as  a  pervious  tube.  In  the  female  subject,  the  round 
ligament  enters  the  internal  ring  in  place  of  the  spermatic 


ANATOMY    OP    INGUINAL    HERNIA.  171 

cord,  and  also  carries  before  it  a  pouch  of  peritoneum,  but 
only  for  a  short  distance  ;  the  diverticulurn,  which  the  peri- 
toneum forms,  is  called  the  canal  of  Nuck. 

DIRECT  INGUINAL  HERNIA  commences  in  the  internal 
inguinal  fossa,  in  a  triangle,  called  the  triangle  of  Hessel- 
bach,  formed  by  the  external  edge  of  the  rectus  muscle, 
Poupart's  ligament,  and  the  obliterated  hypogastric  artery  ; 
it  carries  before  it  the  peritoneum  which  forms  the  sac  of 
the  hernia,  the  transversalis  fascia,  the  conjoined  tendon 
(this,  however,  it  sometimes  splitg,  and  passes  through, 
instead  of  pushing  before  it),  the  spermatic  fascia,  the 
superficial  fascia,  and  the  skin;  it  then  descends  toward  the 
scrotum.  The  epigastric  artery  and  the  spermatic  cord 
are  both  left  upon  the  outer  side  of  this  form  of  hernia, 

OBLIQUE  INGUINAL  HERNIA  commences  in  the  external 
inguinal  fossa,  and  from  that  derives  its  peritoneal  sac ; 
the  internal  inguinal  ring  entered,  it  pushes  before  it  the 
infundibuliform  fascia,  and  when  in  the  canal,  the  cremaster 
muscle ;  at  the  external  ring,  the  spermatic  fascia,  the 
superficial  fascia,  and  the  skin ;  it  then  descends  toward 
the  scrotum.  In  this  form  of  hernia,  the  spermatic  cord  is 
beneath,  and  behind  the  tumor  formed  by  it ;  the  epigastric 
artery  is  upon  the  inside,  the  reverse  of  its  position  in  direct 
hernia.  Oblique  hernia,  from  its  size  and  long  existence, 
may  so  enlarge  and  drag  upon  the  internal  ring,  as  to  bring 
it  behind  the  external  ring,  and  thus  assume  the  appearance 
of  a  hernia  primarily  direct.  The  artery,  of  course,  retains 
its  relative  position. 

When  the  portion  of  peritoneum,  carried  before  the  testi- 
cle in  its  descent,  has  not  been  obliterated,  and  the  intes- 
tine passes  through  the  tube  thus  left,  into  the  tunica  vagi- 
nalis  testis,  it  is  called  a  congenital  hernia.  When  this  tube  is 
partially  obliterated,  and  admits  the  intestine  into  its  upper 
part  only,  it  pushes  down  behind  that  portion  which  has 
formed  the  tunica  vaginalis  testis,  and  is  called  an  encysted, 
or  infantile  hernia.  Inguinal  hernia  rarely  occurs  in  the 
female,  but  all  the  various  forms  have  been  noticed  ;  in 
females  the  hernia  descends  into  the  labia  pudendi. 


172  ANATOMY    OF    THE    ABDOMEN,    ETC. 


DISSECTION  II. 

VISCERAL    CAVITY. 

In  opening  the  abdomen,  a  thin  peritoneal  lamina,  ex- 
tending from  the  umbilicus  to  the  liver,  will  be  seen;  this  is 
the  broad  ligament  of  the  liver ;  in  the  free  border  of  this,  is 
a  round  cord  of  considerable  size,  called  the  round  liga- 
ment, being  the  obliterated  umbilical  vein  of  foetal  life. 
These  should  be  examined,  at  this  time,  as  so  good  an  idea 
of  them  cannot  be  obtained  after  their  division.  Hernia 
may  occur  at  the  umbilicus,  especially  during  infancy,  be- 
fore the  parts  have  consolidated.  Its  course  is  direct,  and 
it  has  for  its  coverings  the  integument,  superficial  fascia,  a 
prolongation  from  the  tendinous  margin  of  the  abdominal 
opening,  the  fascia  transversalis,  and  peritoneum. 

The  abdomen  is  now  to  be  opened,  by  incising  longitudinally  and 
transversely,  whatever  of  the  anterior  parietes  remains,  and  reflecting 
the  flaps  thus  made. 

The  YISCERAL  CAVITY  being  exposed,  it  will  be  remarked 
that  the  intestinal  tube,  with  its  various  divisions  and  con- 
volutions, occupies,  apparently,  the  whole  of  the  abdomen, 
the  only  viscus  attracting  attention  at  the  first  glance  being 
the  liver.  The  intestines  will  be  found  partially  covered, 
superficially,  with  a  membranous  flap,  or  apron  ;  at  times 
this  is  crumpled  up  (so  to  speak),  and  lies  a  confused  mass, 
occupying  but  a  small  space ;  it  may,  however,  be  spread 
out ;  it  is  called  the  great  omentum.  Occupying  the  upper 
part  of  the  cavity,  and  in  close  apposition  to  the  dia- 
phragm, will  be  seen  the  liver;  partly  covered  by  the  liver, 
and  filling  the  left  side,  is  the  stomach,  behind  which  may 
be  found  the  spleen.  Below  the  stomach,  and  stretching 
across  the  spine,  is  the  pancreas.  From  the  stomach  may 
be  traced  the  small  intestine ;  near  the  union  of  this  with 
the  stomach  the  surrounding  parts  will  often  be  found  dis- 
colored by  bile  which,  after  death,  transudes  through  the 
walls  of  the  gall-bladder.  The  small  intestine  occupies  the 
central  part  of  the  visceral  cavity  and  the  pelvis ;  by  run- 
ning it  through,  from  its  commencement,  it  will  be  found 
that  it  joins  the  large  intestine,  or  colon,  in  the  right 
inguinal  region.  The  large  intestine  ascends  on  the  right 
side,  covering  in  the  kidney,  and  is  called  the  ascending 


PERITONEUM.  173 

colon ;  it  crosses  the  abdomen  at  its  upper  part,  under  the 
name  of  the  transverse  colon,  descends  upon  the  left  side, 
as  the  descending  colon,  covering  in  the  left  kidney,  to  the 
left  inguinal  region,  where  it  forms  several  folds,  called  the 
sigmoid  flexure,  and  then  dipping  into  the  pelvis  behind 
the  bladder  becomes  the  rectum. 

All  the  viscera,  so  far  as  they  can  be  seen,  as  well  as  the 
walls  of  the  abdomen,  will  be  found  covered  with  a  thin, 
shining  membrane,  called  the  peritoneum ;  this  facilitates 
the  movements  of  the  various  organs,  which  are  by  no 
cans  inconsiderable,  the  position  of  the  body  influencing 
ery  greatly  the  position  of  the  viscera.  They  have,  not- 
withstanding, been  located  in  regions,  and  though  the 
l)ou ndaries  are  merely  arbitrary,  and  are  indicated  only  in 
the  most  general  way  as  including  the  organs  within  their 
limits,  allusion  is  constantly  made  to  them. 

It  will  be  found  convenient  to  indicate  these  regions  by  strings, 
which  should  be  stretched  in  the  directions  about  to  be  enumerated, 
viz.  :  two  vertical  lines,  each  from  the  most  dependent  portions  of  the 
cartilages  of  the  eighth  ribs  to  tbe  centre  of  Poupart's  ligament ;  a 
transverse  line  corresponding  to  the  summits  of  the  ilia,  and  another 
to  the  most  dependent  portion  of  the  ribs. 

We  thus  have  three  zones,  each  subdivided  into  three 
regions.  The  three  in  the  upper  zone  are,  lateralty,  the 
right  and  left  hypochondriac,  in  the  centre,  the  epigastric. 
In  the  middle  zone,  laterally,  the  right  and  left  lumbar,  and 
in  the  centre  the  umbilical.  In  the  lower  zone,  laterally, 
the  right  and  left  inguinal,  and  in  the  centre  the  hypogas- 
t/'ic.  By  handling  the  abdominal  contents,  the  student  can 
satisfy  himself  that  the  right  hypochondriac  region  con- 
tains the  liver,  the  left  the  spleen,  and  part  of  the  stomach, 
while  the  epigastric  contains  a  part  of  both  the  stomach 
and  the  liver;  the  lumbar  regions  contain  the  kidneys  on 
either  side  ;  the  umbilical  the  small  intestines  ;  the  right 
inguinal  region  contains  the  caecum,  the  left  the  sigmoid 
flexure ;  the  hypogastric  region  contains  the  bladder  and 
rectum,  and  in  the  female,  the  uterus. 

PERITONEUM. 

The  PERITONEUM  is  a  serous  membrane.  Considered  in 
its  simplest  form,  a  serous  membrane  is  a  hollow  sac,  into 
which  a  viscus  protrudes  itself,  and  thus,  while  getting  a 
covering  itself,  lies  within  another  covering  of  the  same 

15* 


174  ANATOMY    OF    THE    ABDOMEN,    ETC. 

membrane,  reflected  from  its  own  walls.  We  have  only 
conceive  this  sac  as  large  enough  to  admit  of  many  viscera 
protruding  into  it,  and  we  have  an  idea  of  the  peritoneum 
some  of  the  viscera  it  merely  passes  over,  without  invest 
ing  them  on  all  their  sides,  and  all  of  them  are,  in  reality, 
outside  the  membrane.  The  folds  made  by  the  peritoneum, 
either  in  its  reflections  from  the  viscera  which  it  has  in- 
vested, or  in  passing  from  one  organ  to  another,  constitute 
means  of  support,  and  hold  them  in  their  proper  places ; 
these  in  certain  instances  are  improperly,  though  very  con- 
veniently, called  ligaments,  in  others  omenta,  and  in  still 
other  instances  mesenteries;  besides  supporting  the  organs, 
they  contain  the  various  vessels  and  nerves  destined  to  the 
different  parts. 

The  great  amentum  is  formed  by  two  folds  of  the  peritoneum,  which 
descend  from  the  larger  curvature  of  the  stomach,  covering  in  the  small 
intestines,  then,  doubling  upon  themselves,  they  return  to  be  attached 
to  the  transverse  colon  ;  it  therefore  consists  of  four  thicknesses  ;  they 
are  not,  however,  easily  separable.  The  great  omentum  contains  a 
variable  amount  of  fat,  is  sometimes  perforated  with  holes,  aud  is 
not  unfrequently  gathered  up  in  a  mass  near  the  stomach. 

The  lesser  omentum  is  the  fold  extending  between  the  smaller  curva- 
ture of  the  stomach  and  the  liver;  it  contains  the  portal  vein,  hepatic 
artery  and  ducts ;  its  left  side  is  continuous  with  the  oesophagus,  but 
its  right  forms  a  free  margin,  beneath  which  the  finger  may  be  passed 
into  the  cavity  of  the  peritoneum  behind  the  stomach  ;  this  passage 
is  called  the  foramen  of  Winslow. 

The  gastro-splenic  omentum  passes  from  the  outer  border  of  the  sto- 
mach to  the  spleen,  and  contains  the  splenic  vessels. 

The  mesentery  proper  is  that  fold  of  the  peritoneum  which  holds 
down  the  small  intestine,  and  which  is  attached  posteriorly  to  the 
front  of  the  spine  ;  it  is  about  four  inches  wide,  and  between  its  two 
layers,  besides  a  considerable  amount  of  fat,  are  the  arteries,  veins, 
and  nerves  of  the  small  intestine,  also  the  lymphatic  vessels  and 
glands,  called  the  mesenteric  glands. 

The  transverse  meso-colon  is  the  mesentery  of  the  transverse  colon, 
and  its  medium  of  connection  with  the  posterior  wall  of  the  abdomen. 

The  meso-rectum  and  meso-ccecum  are  similar  folds  connected  with  the 
rectum  and  caecum.  The  meso-csecum  is  of  such  length  as  to  permit 
great  mobility  to  the  caecum,  though  it  is  usually  described  as  closely 
bound  to  the  iliac  fossa.  A  left  inguinal  hernia  of  the  caecum  may 
occur. 

The  complications  of  the  peritoneum  are  not  easily  com- 
prehended, and  it  is  only  after  a  good  deal  of  thought  and 
repeated  examination  that  they  can  be  fully  understood. 
In  tracing  the  continuity  of  this  membrane  from  above 
downward,  the  student  begins  at  the  liver,  where  he  will 


PERITONEUM.  175 

perceive  that  it  is  prolonged  from  the  under  surface  of  that 
viscus  on  to  the  vessels.  u  From  the  liver  it  may  be  fol- 
lowed along  the  vessels,  one  la}rer  before  and  the  other 
behind  them,  forming  the  lesser  omentum,  to  the  upper 
border  of  the  stomach.  At  the  stomach  the  two  layers  in- 
closing the  vessels  separate,  one  going  before  and  the  other 
behind  it ;  but  beyond  that  viscus  they  are  applied  to  one 
another  to  form  the  great  omentum.  After  descending  in 
contact  in  that  fold  to  the  lower  part  of  the  abdomen,  they 
may  be  traced  in  it  backward  and  upward,  and  may  be  seen 
to  separate  to  inclose  the  transverse  colon,  like  the  sto- 
mach, and  then  to  continue  to  the  spine,  giving  rise  to  the 
transverse  meso-colon.  At  the  attachment  to  the  spine 
the  two  companion  layers  will  be  found  to  separate,  one 
passing  upward  and  the  other  downward.  The  ascending 
layer  is  continued  in  front  of  the  pancreas  and  the  pillars 
of  the  diaphragm,  and  blends  with  the  peritoneum  on  the 
posterior  aspect  of  the  liver.  The  descending  layer  may 
be  followed  from  the  transverse  meso-colon  along  the  mid- 
dle line  of  the  spine,  over  the  duodenum,  the  aorta,  and  vena 
cava,  till  it  meets  with  the  artery  to  the  small  intestine, 
along  which  it  is  continued  to  form  the  mesentery,  turning 
over  the  intestine  and  back  to  the  spine  along  the  other 
aspect  of  the  vessels.  From  the  root  of  the  mesenteric 
artery  the  peritoneum  descends  to  the  pelvis,  and  partly 
covers  the  viscera  in  that  cavity ;  thus  it  surrounds  the 
upper  part  of  the  rectum,  and  attaches  this  viscus  to  the 
abdominal  wall  by  the  meso-rectum ;  next,  it  is  continued 
forward  between  the  rectum  and  the  bladder,  or  between 
the  rectum  and  the  uterus,  where  it  forms  a  pouch ;  thence 
it  passes  over  the  back  and  sides  of  the  bladder.  Lastly, 
the  serous  membrane  is  continued  to  the  inguinal  region, 
where  it  forms  the  fossae,  before  alluded  to  (p.  170),  and  it 
can  be  traced  upward  on  the  anterior  wall  of  the  abdomen 
and  the  diaphragm,  to  the  rest  of  the  membrane  on  the 
upper  surface  of  the  liver."1 

The  peritoneum  may  also  be  traced  in  a  transverse  direc- 
tion. Beginning  at  the  umbilicus,  it  may  be  followed  out- 
ward to  the  large  intestine,  which  it  fixes  to  the  abdominal 
wall  by  the  meso-colon,  over  the  kidney  to  the  middle  line, 
along  the  vessels  to  the  small  intestine,  round  the  intes- 
tine and  back  to  the  spine  along  the  other  aspect  of  the 

1  Ellis's  Demonstrations  of  Anatomy. 


176 


ANATOMY     OF     TILE     ABDOMEN,    ETC 


vessels,  and  so  outward  over  the  large  intestine  of  th< 
opposite  side,  to  the  parietes  of  the  abdomen  and  the 
umbilicus. 

DUCTS,  VESSELS,  AND  NERVES  OF  THE  ABDOMINAL  CAVITY. 


By  raising  the  edge  of  the  liver  and  drawing  the  intestines  down- 
ward, the  biliary  ducts,  situated  in  the  lesser  omentum  and  lying 
between  the  two  peritoneal  layers  forming  the  pillar  of  the  foramen 
of  Wiuslow,  may  be  examined. 

From  the  duodenum  a  duct  of  variable  size  can  be  traced 
backward  toward  the  liver ;  this  is  the  ductus  choledochus 
communis ;  it  divides  as  it  approaches  the  liver  into  two 
branches,  one  of  which  comes  from  the  neck  of  the  gall- 
bladder, and  is  called  the  cystic  duct,  the  other,  coming  from 
the  transverse  fissure  of  the  liver,  the  hepatic  duct;  they 
are  accompanied  by  the  hepatic  artery  and  portal  vein. 

The  veins  of  the  portal  system  may  be  found  by  pushing  aside  the 
viscera  and  searching  for  them  in  the  regions  to  which  they  belong ; 
it  is  impossible  to  dissect  them  without  making  special  preparation 
for  so  doing. 

The  PORTAL  VEIN  or  SYSTEM  is  composed  of  those  ves- 
sels which  return  the  blood  from  the  chylopoietic  viscera ; 
they  are  the 


Inferior  Mesenteric, 
Superior  Mesenteric, 


Splenic, 
Gastric. 


The  inferior  mesenteric  vein  returns  the  blood  from  the  rectum, 
sigmoid  flexure  and  ascending  colon,  terminating  in  the  splenic  vein. 

The  superior  mesenteric  vein  returns  the  blood  distributed  by  the 
superior  mesenteric  artery;  it  ascends  in  company  with  that  vessel, 
and  behind  the  pancreas  unites  with  the  splenic  vein. 

The  splenic  vein  commences  in  the  spleen  by  several  branches, 
which,  uniting,  form  a  large  trunk  which  passes  behind  the  pancreas, 
receiving  the  gastric  veins  from  the  stomach  and  duodenum.  The 
union  of  this  with  the  superior  and  inferior  mesenteric  veins  forms 
the  portal  vein. 

The  portal  vein  lies  in  the  lesser  omentum,  between  the  biliary  ducts 
and  hepatic  artery;  it  ascends  to  the  transverse  fissure  of  the  liver, 
where  it  divides  into  two  branches,  one  for  the  right  and  the  other  for 
the  left  lobe. 

The  arteries  of  the  various  abdominal  viscera  all  come  from  the 
abdominal  aorta  ;  the  nerves  from  the  pneumogastric  and  from  the 
sympathetic  ganglia.  Their  dissection  is  one  of  considerable  diffi- 
culty, owing  to  the  mobility  of  the  viscera  and  the  constant  necessity 
of  changing  their  position,  so  as  successfully  to  expose  the  different 
trunks  The  aorta  should  first  be  found  at  the  point  where  it  per- 


DUCTS,   VESSELS,   AND    NERVES,    ETC.  177 

forates  the  diaphragm,  then,  by  removing  the  peritoneum,  each  artery, 
as  it  presents  itself,  is  to  be  followed  out  by  such  means  as  the  dis- 
sector's ingenuity  will  suggest.  The  nerves  will  some  of  them  be 
exposed  with  the  arterial  trunks  which  they  accompany ;  a  detailed 
dissection  of  them  is  rarely  accomplished  ;  being  composed  of  plexuses 
proper  to  each  organ,  they  are  usually  made  the  subject  of  special 
dissections.  More  than  to  trace,  to  some  slight  extent,  the  connection 
of  these  plexuses  with  the  principal  ganglia  of  the  sympathetic,  can 
hardly  be  expected.  The  student,  therefore,  need  not  be  disappointed 
if  he  is  unable  to  verify  those  paragraphs  marked  with  an  asterisk. 

The  nervous  plexuses  of  the  abdomen  may  be  enumerated 

follows: — 

Solar,  Superior  Mesenteric, 

Phrenic,  Aortic, 

Supra-renal,  Inferior  Mesenteric, 

Gastric,  Renal, 

Hepatic,  Spermatic, 

Splenic,  Hypogastric. 

In  searching  for  the  cceliac  axis,  which  lies  behind  the 
stomach,  the  SOLAR  PLEXUS  will  be  seen  encircling  the 
coeliac  axis,  covering  the  aorta,  and  spreading  out  in  all 
directions;  it  is  joined  by  the  greater  splanchnic  nerve  of 
both  sides  (p.  122),  and  receives  branches  from  the  pneu- 
mogastric  and  phrenic  nerves.  The  solar  plexus  contains 
a  number  of  ganglia,  the  principal  one  of  which  is  called 
the  SEMILUNAR  GANGLION,  and  the  radiation  of  nerves 
from  this  gives  the  plexus  its  name  of  solar.  From  this 
plexus  arise  those  branches  which  form  the  phrenic  and 
supra-renal  plexuses  ;  these  may  also  be  seen  at  this  stage 
of  the  dissection. 

The  ABDOMINAL  AORTA  commences  at  the  aortic  opening 
of  the  diaphragm,  and,  descending  on  the  left  side  of  the 
vertebral  column,  terminates  by  dividing  into  the  two  com- 
mon iliac  arteries. 

The  CCELIAC  Axis  is  the  first  large  trunk  given  off  by 
the  abdominal  aorta.  The  phrenic  arteries  are  normally 
the  first,  but  they  are  extremely  irregular  in  their  origin, 
and  as  often  arise  from  the  cceliac  axis  as  from  the  aorta ; 
they  are  two  in  number,  and  ascend  obliquely  outward, 
ramifying  on  the  under  surface  of  the  diaphragm ;  their 
inosculations  with  other  arteries  are  very  numerous,  and 
they  send  a  branch  to  the  supra-renal  capsule  on  both  sides. 
The  cceliac  axis  is  a  short  but  large  trunk,  which  arises 
close  to  the  diaphragm  and  quickly  divides  into  three 


178      ANATOMY  OF  THE  ABDOMEN,  ETC. 

branches,  the  gastric,  hepatic,  and  splenic.  Each  of  the* 
branches  conveys  the  plexus  of  nerves  destined  for  the 
organ  to  which  it  is  distributed,  and  it  may  be  seen  si 
rounding  the  artery  as  a  sort  of  sheath.  The  coeliac  axis 
may  be  wanting,  its  branches  originating  directly  from  the 
aorta ;  or  it  may  give  off  but  two  branches,  the  gastrk 
and  the  splenic,  the  hepatic  coming  from  some  other  source, 
as,  for  instance,  the  superior  mesenteric  or  the  aorta. 

The  gastric  artery  is  distributed  to  the  smaller  curvature  of  the 
stomach;  it  joins  it  near  the  oesophagus,  to  which  it  gives  some 
ascending  branches,  while  others  pass  round  the  cardiac  extremity 
to  join  the  vasa  brevia  of  the  splenic  artery;  its  terminal  branch 
unites  with  the  pyloric  branch  of  the  hepatic. 

The  hepatic  artery  curves  up  toward  the  liver,  and  is  in  close  relation 
with  the  hepatic  duct  and  portal  vein  ;  near  the  pylorus  it  gives  off  a 
pyloric  branch  to  the  lesser  curvature  of  the  stomach,  where  it  inoscu- 
lates with  the  gastric,  and  also  the  gastro-duodenalis,  which  supplies 
the  stomach  and  duodenum  ;  the  gastro-duodenalis  divides  into  the 
qastro-epiploica  dextra,  which  is  distributed  to  the  larger  curvature  of 
the  stomach  and  anastomoses  with  the  splenic,  and  into  the  pancrea- 
tico-duodenalis,  supplying  the  duodenum  and  pancreas,  and  anasto- 
mosing with  the  superior  mesenteric.  The  hepatic  at  its  termination 
divides  into  two  branches  which  enter  the  transverse  fissure  of  the 
liver  and  separate  to  its  right  and  left  lobes.  A  small  branch,  the 
cystic,  is  given  off  by  one  of  these  to  the  gall-bladder.  Accessory 
hepatic  arteries  are  frequently  found,  usually  coming  from  the  gastric 
artery. 

The  splenic  artery  is  the  largest  branch  of  the  coeliac  axis  ;  it  sup- 
plies the  spleen,  pancreas,  and  stomach  ;  it  passes  outward  in  a  tortu- 
ous manner,  behind  the  pancreas,  and  divides  into  numerous  terminal 
branches  which  penetrate  the  hilus  of  the  spleen;  the  splenic  vein  is 
in  close  relationship  with  it.  It  reflects  several  small  branches  to  the 
great  end  of  the  stomach  which  are  called  vasa  brevia,  and  a  single 
large  branch  passes  along  the  greater  curvature  of  the  stomach,  under 
the  name  of  gastro-epiploica  sinistra,  anastomosing  with  a  branch  from 
the  hepatic.  Numerous  small  twigs  are  given  off  to  the  pancreas. 

The  SUPERIOR  MESENTERIC  ARTERY  arises  from  the  front 
of  the  aorta  just  below  the  coeliac  axis,  sometimes  in  con- 
nection with  that  trunk.  A  portion  of  this  artery  at  its 
commencement  is  covered  in  by  the  pancreas,  to  which  it 
sends  a  small  branch;  it  divides  into  numerous  branches, 
which,  placed  parallel  to  each  other,  descend  between  the 
two  layers  of  the  mesentery,  and  then  by  a  series  of  vas- 
cular arches,  rarely  if  ever  exceeding  three  in  number, 
supplies  the  small  intestine  from  the  duodenum  to  its  ter- 
mination in  the  colon ;  these  arches  anastomose  so  freely 
with  each  other,  that  the  circulation  at  any  one  point  can 
never  be  interrupted  by  the  compression  of  the  intestinal 


DUCTS,    VESSELS,    AND    NERVES,    ETC.  179 

folds.  Besides  supplying  the  small  intestine,  the  mesenteric 
artery  sends  a  separate  division,  called  the  ileo-colic,  to  the 
caecum  and  termination  of  the  ileum;  another  single  divi- 
sion supplies  the  ascending  colon,  and  is  called  the  colica 
dextra;  a  third  branch  supplies  the  transverse  colon,  being 
called  the  colica  media;  these  three  trunks  anastomose 
together  by  their  terminal  branches,  and  the  last  named 
inosculates  with  the  colica  sinistra,  a  branch  of  the  inferior 
mesenteric,  which  supplies  the  descending  colon  and  sig- 
moid  flexure,  "and  so  completes,"  says  John  Bell,  uthe 
great  mesenteric  arch,  one  of  the  most  celebrated  inoscula- 
tions in  the  whole  body,  that  of  the  circle  of  Willis  hardly 

:cepted." 

*  These  several  branches  of  the  mesenteric  artery  are 
accompanied  by  the  nerves  which  constitute  the, superior 
mesenteric  plexus ;  they  can  be  found,  together  with  several 
ganglionic  masses,  at  the  commencement  of  the  artery, 
which  they  surround,  and  may  be  traced  back  to  the  solar 
plexus ;  they  supply  the  pancreas  and  intestinal  canal. 

In  the  intervals  of  the  branches  of  the  mesenteric  vessels 
numerous  lymphatic  glands  are  lodged ;  these  are  called 
the  mesenteric  glands ;  the  chyliferous  vessels  of  the  small 
intestine  pass  through  these  to  reach  the  thoracic  duct ; 
these  glands  are  often  enlarged  by  disease. 

The  INFERIOR  MESENTERIC  ARTERY  arises  about  two 
inches  below  the  superior,  also  from  the  front  of  the 
aorta;  it  inclines  to  the  left,  and  by  a  series  of  arches 
supplies  the  descending  colon  under  the  name  of  the  colica 
ftini.xtra,  forming  large  and  free  anastomoses  with  the 
colica  media  of  the  superior  mesenteric ;  a  second  branch 
passes  to  the  sigmoid  flexure,  and  is  called  the  sigmoid 
nrfrry,  and  its  terminal  branch  goes  to  the  mesentery  of 
the  rectum,  under  the  name  of  the  superior  hemorrhoidal 
(irfrry ;  these  three  branches  anastomose  freely  with  each 
other. 

:  The  front  of  the  aorta,  between  the  mesenteric  arteries, 
is  covered  by  the  aortic  plexus  of  nerves ;  this  connects 
with  the  solar  plexus,  and  also  unites  with  the  lumbar 
ganglia,  situated  upon  the  sides  of  the  vertebrae ;  from  it 
passes  off  the  inferior  mesenteric  plexus,  which,  accom- 
panying the  artery  of  that  name,  supplies  the  parts  to 
which  that  vessel  is  distributed. 

The  intestines  should  now  be  removed.  To  do  this  the  rectum  is 
to  be  tied  and  divided  ;  the  large  intestine  should  then  be  dissected 


180  ANATOMY    OP    THE    ABDOMEN,    ETC. 

from  the  nieso-colon  close  to  the  intestinal  wall,  and  the  small  intes 
tine  separated   from  the  mesentery  in  a  similar  manner,  tying  am 
dividing  it  just  below  the  duodenum  ;  they  are  then  to  be  set  aside 
for  further  examination,  and  kept  immersed  in  water. 

The  RENAL  ARTERIES  are  given  off  at  right  angles  from 
the  sides  of  the  aorta,  just  below  the  origin  of  the  superior 
mesenteric  artery;  the  right  is  given  off  lower  down,  and 
is  shorter  than  the  left ;  each  divides  into  several  terminal 
branches  to  enter  the  kidney  at  its  hilus  ;  occasionally  they 
penetrate  through  the  sides  of  the  organ.  The  aorta 
sometimes  gives  off  two,  three,  and  even  four,  renal  arte- 
ries to  one  kidney,  and  they  often  vary  in  arrangement  on 
the  two  sides  of  the  body. 

*  The  renal  plexus  lies  upon  the  renal  artery,  and  is 
composed  of  branches  from  the  solar  and  aortic  plexuses ; 
the  inferior  and  renal  splanchnic  nerves  (p.  122)  also  ter- 
minate in  this  plexus.     Ganglia  of  various  size  occur  in 
it,  and  its  branches  ramify  upon  and  in  the  substance  of 
the  kidney. 

A  small  branch  from  the  side  of  the  aorta  just  above  the 
renal  artery  goes  to  the  supra-renal  capsule,  and  is  called 
the  SUPRA-RENAL  ARTERY.  The  capsule  usually  receives 
a  branch  from  the  renal  and  also  from  the  phrenic  arteries. 

The  SPERMATIC  ARTERIES  are  two  long  and  slender 
branches  given  off  from  the  front  of  the  aorta,  just  below 
the  origin  of  the  renal  arteries ;  occasionally  they  arise  by 
a  common  trunk ;  sometimes  there  are  two  upon  one  side, 
and  their  origin  may  be  from  the  renal  artery.  They  pass 
downward  beneath  the  peritoneum,  crossing  the  ureter  and 
external  iliac  artery,  to  the  internal  inguinal  ring,  and  then 
accompany  the  spermatic  cord  to  the  testis.  In  the  female 
these  arteries  are  called  the  ovarian,  and  instead  of  passing 
out  of  the  abdominal  cavity,  they  dip  into  the  pelvis,  and 
pass  up  between  the  layers  of  the  broad  ligament  of  the 
uterus  to  the  ovaries.  The  length  of  these  vessels  will  be 
accounted  for,  when  it  is  remembered  that  the  testicle 
descends  at  the  close  of  intra-uterine  life  to  the  scrotum 
from  the  lumbar  region,  and  that  the  ovary,  during  preg- 
nancy, is  lifted  with  the  uterus  above  the  umbilicus ;  it  is 
therefore  for  the  purpose  of  accommodating  these  dis- 
placements of  the  organs  to  which  they  are  distributed. 

*  The  spermatic  plexus  accompanies  the  spermatic  arte- 
ries ;  it  is  formed  by  branches  from  the  renal  and  aortic 
plexuses. 


DUCTS,    VESSELS,    AND     NERVES,    ETC.  181 

The  spermatic  veins  accompany  the  spermatic  arteries  in 
a  part  of  their  course ;  they  are  formed  by  the  union  of 
several  venous  branches  which  surround  the  spermatic 
cord,  and  ascend  as  single  trunks,  the  right  to  enter  the 
vena  cava  and  the  left  to  join  the  left  renal  vein.  It  has 
been  attempted  to  explain  the  more  frequent  occurrence  of 
varicocele  upon  the  left  side,  by  the  less  direct  entrance  of 
the  blood  from  the  vein  of  that  side  into  the  general  cir- 
culation. 

The  abdominal  aorta  will  be  found  to  terminate  in  two 
branches  at  the  level  of  the  third  lumbar  vertebra,  ^called 
the  COMMON  ILIAC  ARTERIES  ;  these  diverge,  and  divide, 
opposite  the  union  of  the  sacrum  with  the  os  innominatum, 
into  external  and  internal  iliac  arteries  ;  the  former  courses 
along  the  brim  of  the  pelvis  to  pass  out  beneath  Poupart's 
ligament,  and  become  the  artery  of  the  lower  extremity ; 
the  latter  dips  into  the  pelvis  to  supply  the  viscera  it  con- 
tains. In  negroes  and  in  old  subjects,  the  common  and 
external  iliac  arteries  are  often  curved  and  tortuous. 
Lymphatic  glands  will  be  found  along  their  course. 

At  the  point  of  the  aorta's  bifurcation  a  small  artery 
arises  called  the  SACRA  MEDIA;  it  descends  on  the  mid- 
dle line  of  the  sacrum,  giving  off  short  branches  upon 
either  side  in  its  course  toward  the  coccyx,  where  it  termi- 
nates. It  sometimes  arises  from  the  left  common  iliac. 

The  lumbar  ganglia,  forming  part  of  the  continuous  chain 
of  the  ganglia  of  the  sympathetic,  which  extends  from  the 
head  to  the  coccyx,  should  now  be  dissected ;  their  con- 
nection with  the  anterior  branches  of  the  spinal  nerves  can 
also  be  traced.  The  ganglia  will  be  found  much  larger  in 
size  than  those  in  the  thoracic  region ;  they  also  lie  closer 
together;  upon  the  right  side  they  are  covered  in  by  the 
vena  cava,  on  the  left  they  rest  upon  the  vertebrae  along 
the  edge  of  the  psoas  muscle.  The  branches  which  com- 
municate with  the  anterior  spinal  nerves  are  of  consider- 
able length  and  accompany  the  lumbar  arteries,  passing 
beneath  the  tendinous  fibres  by  which  the  psoas  muscle 
arises. 

*  These  ganglia  give  origin  to  the  h3Tpogastric  plexus, 
which  lies  upon  the  anterior  surface  of  the  sacrum  and 
last  lumbar  vertebrae,  and  distributes  its  branches  to  the 
viscera  of  the  pelvis. 

The  LUMBAR  ARTERIES  are  four  in  number,  and  corre- 
spond to  the  intercostal  branches  of  the  thoracic  aorta. 
16 


182  ANATOMY    OF    TUB    ABDOMEN,    ETC. 

They  arise  from  the  posterior  aspect  of  the  aorta,  those  of 
the  right  side  being  the  longest  and  covered  in  by  the  vena 
cava ;  passing  over  the  bodies  of  the  vertebrae  they  dip 
beneath  the  psoas  muscle  and  divide  into  two  branches, 
one  of  which  goes  to  the  spinal  cord  and  spinal  muscles, 
while  the  other  continues  its  course  forward  to  the  abdo- 
minal muscles.  The  first  lumbar  artery  passes  under  the 
pillar  of  the  diaphragm,  and  along  the  edge  of  the  last 
rib ;  the  last  lumbar  passes  along  the  crest  of  the  ilium. 
The  lumbar  arteries  of  the  opposite  sides  sometimes  arise 
by  a  common  trunk,  which  sends  out  its  branches  laterally  ; 
two  arteries  of  the  same  side  are  sometimes  conjoined  at 
their  origin. 

The  EXTERNAL  ILIAC  YEIN  is  the  continuation  of  the 
femoral  vein,  and  will  be  found  accompanying  the  external 
iliac  artery ;  at  Poupart's  ligament  it  lies  on  the  inside  of 
the  artery,  but  gradually  get.s  beneath  it ;  it  is  joined  by 
the  internal  iliac  vein,  which  returns  the  blood  from  the 
penis  and  pelvic  viscera.  These  two  veins  form  the  com- 
mon iliac  veins,  which,  uniting  upon  the  right  side  of  the 
aorta,  form  the  VENA  CAVA  INFERIOR  ;  this  ascends  along 
the  right  side  of  the  abdominal  aorta,  receiving  in  its  course 
the  lumbar  veins,  which  accompany  the.lumbar  arteries,  the 
left  being  the  longest ;  the  renal,  which  lie  in  front  of  the 
renal  arteries,  the  left  renal  crossing  the  aorta  and  being 
the  longest;  the  supra-renal,  which,  however,  sometimes 
terminate  in  the  renal ;  the  phrenic,  returning  the  blood 
from  .the  diaphragm,  and  the  hepatic,  which  empties  the 
blood  from  the  portal  system  and  the  hepatic  artery.  The 
phrenic  and  hepatic  veins  cannot  be  seen  until  the  liver  is 
removed.  The  spermatic  veins  are  long  and  slender  veins 
accompanying  the  spermatic  arteries ;  the  right  spermatic 
enters  the  front  of  the  vena  cava,  the  left  spermatic  enters 
the  left  renal  vein  ;  these  return  the  blood  from  the  scrotum 
and  testicles.  The  vena  cava  passes  out  of  sight  beneath 
the  liver,  where  it  traverses  a  groove  in  that  organ  destined 
for  it,  and  passing  through  a  special  opening  in  the  dia- 
phragm, penetrates  the  pericardium  and  terminates  in  the 
right  auricle  of  the  heart.  The  vena  azygos  major  and 
minor  (p.  123),  originate  from  the  lumbar  veins,  and  pass 
up  beneath  the  diaphragm  to  unite  with  the  vena  cava 
superior. 


u 


INTESTINAL    TUBE.  183 


DISSECTION  III. 

INTESTINAL    TUBE. 

The  intestines  must  be  washed  before  they  can  be  examined,  but 
it  should  never  be  done  until  they  are  opened  ;  this  may  be  accom- 
plished by  the  scissors,  or  by  a  special  instrument  called  an  entero- 
tome  ;  the  section  should  be  made  along  the  line  of  attachment  of 

e  mesentery. 

The  portion  of  the  alimentary  canal  known  as  the  INTES- 
TINES, extends  from  the  stomach  to  the  anus,  and  is  divided 
into  the  small  and  large  intestine.  The  small  intestine  ex- 
tends from  the  pylorus  to  the  caecum,  the  large  from  the 
caecum  to  the  anus  ;  they  differ  from  each  other  in  structure 
as  well  as  size,  the  first  being  of  uniform  calibre,  and  the 
second  much  larger,  and  of  a  sacculated  and  irregular  out- 
line. 

The  small  intestine,  about  twenty  feet  in  length,  is  arbi- 
trarily divided  into  three  portions,  duodenum,  jejunum,  and 
ileura.  The  duodenum  is  the  first  twelve  inches  beyond  the 
stomach;  the  jejunum  is  the  first  two  fifths  of  the  remain- 
ing portion;  the  lower  three  fifths  constitute  the  'ileum, 
which  terminates  in  the  caecum. 

The  large  intestine,  or  colon,  about  five  feet  in  length,  is 
divided  into  the  caecum,  or  caput  coli,  the  ascending,  trans- 
verse, and  descending  colon,  the  sigmoid  flexure,  and  the 
rectum.  Attached  to  the  caecum  is  a  small,  tapering,  tubular 
appendage,  a  little  bulbous  at  its  occluded  extremit}',  from 
three  to  six  inches  in  length,  and  held  in  its  place  by  a  mesen- 
tery proper  to  itself;  it  is  usually  tortuous,  and  about  the 
size  of  a  pipe-stem ;  it  communicates  with  the  interior  of  the 
caecum  through  a  small  orifice,  and  is  called  the  appendix 
vermiformis  cseci.  Two  or  three  longitudinal  bands  run  the 
whole  length  of  the  large  intestine ;  they  are  about  half  an 
inch  wide,  and,  being  shorter  than  the  canal  itself,  give  to 
its  walls  a  sacculated  character. 

To  form  a  proper  idea  of  the  ileo-csecal  valve,  the  caecum  and  a  por- 
tion of  the  ileum  should  be  inflated  and  dried  ;  then  cutting  a  window 
in  the  side,  its  arrangement  may  be  seen. 

The  entrance  of  the  ileum  into  the  large  pouch  of  the 
caecum  is  protected  by  a  valve,  called  the  ileo-csecal,  which 
prevents  regurgitation  of  its  contents  back  into  the  small 


184  ANATOMY    OF    THE    ABDOMEN,    ETC. 

intestine ;  it  is  formed  from  the  mucous  coat  of  the  caecum, 
and,  within  that  part  of  the  intestine,  appears  as  a  trans- 
verse, elliptical  opening,  formed  by  two  lips,  which,  when 
closed,  overlap  each  other,  and  which  any  distension  of  the 
caecum  can  only  close  more  effectually. 

The  walls  of  the  intestines  are  composed  of  four  coats, 
viz  :  peritoneal,  muscular,  cellular,  and  mucous.  The  peri- 
toneal coat  completely  surrounds  the  small  intestine,  its 
two  layers  meeting  to  form  the  mesentery.  With  the 
exception  of  the  caecum,  which  it  wholly  invests,  and 
furnishes  with  a  mesentery,  it  only  partially  covers  the 
large  intestine;  passing  over  its  anterior  portion,  and  then 
being  reflected  on  to  the  parietes  of  the  abdomen,  it  leaves 
the  posterior  wall  in  direct  contact  with  the  iliac  fascia. 
Attached  to  the  peritoneal  surface  of  the  large  intestine, 
small  fatty  bodies  are  sometimes  seen,  hanging  off  in  a 
fringe-like  manner;  they  vary  in  number  and  size,  and  are 
called  appendices  epiploicde.  If  the  peritoneum  be  peeled 
off  from  the  intestine,  the  miLscular  coat,  consisting  of 
longitudinal  and  transverse  fibres,  will  be  seen  beneath  it ; 
the  longitudinal  fibres  are  external  to  the  circular,  but  the 
latter  are  thicker  and  most  developed,  except  in  the  large 
intestine,  where  the  muscular  fibres  are  chiefly  collected  in 
the  longitudinal  bands  characteristic  of  that  part  of  the 
tube.  The  mucous  coat  is  continuous  throughout  the  whole 
alimentary  canal.  In  the  upper  part  of  the  small  intestine 
it  lies  in  a  series  of  transverse  folds,  called  valvulse  conni- 
ventes ;  these  gradually  disappear  in  the  ileum.  In  the 
large  intestine  it  is  thrown  into  sharp  ridges,  correspond- 
ing to  the  constrictions  of  its  sacculi.  The  sub-mucous 
cellular  tissue  connecting  the  mucous  and  muscular  coats, 
which  may  be  demonstrated  by  stripping  off  the  mucous 
membrane,  is  sometimes  described  as  a  fourth  coat,  called 
the  cellular. 

The  intestines  are  furnished  with  certain  GLANDS,  which 
may  be  seen  upon  the  surface  of  the  mucous  membrane. 
The  solitary  glands  are  white,  rounded,  and  slightly  promi- 
nent bodies,  scattered  over  the  surface  of  both  large  and 
small  intestine,  in  the  former  being  found  chiefly  in  the 
caecum.  The  follicles  of  Lieberkuhn,  found  also  in  both 
large  and  small  intestine,  consist  of  little  follicles  with  a 
minute  orifice,  hardly  perceptible.  The  agminated,  or  Peyer's 
glands,  belong  chiefly  to  the  ileum,  and  exist  only  in  the 
small  intestine  ;  they  are  of  an  oblong  shape,  have  a  granu- 


INTESTINAL    TUBE.  185 

lated  aspect,  and  are  placed  opposite  the  attachment  of  the 
mesentery  ;  the  number  and  position  of  these  patches  vary, 
but  there  is  almost  always  a  large  one  near  the  termination 
of  the  ileum  in  the  caecum.  The  velvet-like  surface  of  the 
mucous  membrane  of  the  small  intestine  is  made  up  of 
\rilli,  minute  processes  in  which  commence  the  lacteals, 
and  which  are  only  distinctly  visible  with  the  assistance 
of  a  lens. 

The  duodenum,  not  having  been  removed  with  the  rest 
of  the  intestine,  will  be  found  in  situ  ;  it  is  the  first  ten  or 
twelve  inches  of  the  canal  beyond  the  stomach ;  it  has  no 
mesentery,  and  lies  beneath  the  peritoneum,  which  only 
covers  its  anterior  surface;  the  direction  taken  by  it  gives 
it  the  shape  of  a  horseshoe,  the  convexity  of  which  looks 
toward  the  right  side ;  the  head  of  the  pancreas  occupies 
the  concavity,  and  its  duct,  as  well  as  that  of  the  liver, 
opens  into  it  through  the  posterior  wall.  A  form  of  glands, 
called  Brunner's  glands,  is  peculiar  to  this  portion  of  the 
intestine ;  they  are  scattered  in  great  numbers  throughout 
its  whole  extent,  and  give  the  mucous  surface  a  sort  of 
granular  aspect. 

The  STOMACH  is  an  expanded  portion  of  the  alimentary 
canal,  between  the  oesophagus  and  duodenum.  The  oeso- 
phagus, after  passing  through  the  diaphragm,  terminates 
by  gradually  dilating  into  the  stomach.  That  portion  of 
the  stomach  expanding  to  the  left  of  the  oesophagus  is 
called  its  cardiac  extremity,  and  that  at  the  opposite  end 
thepyloric  extremity.  The  superior  curved  border  is  called 
the  lesser  curvature,  and  the  inferior  border  the  greater 
curvature ;  to  these  borders  are  attached  respectively  the 
lesser  and  greater  omentum.  The  stomach  varies  in  size, 
according  to  the  individual,  and  the  degree  of  distension 
by  its  contents,  and  consequently  varies  somewhat  in  the 
position  it  occupies;  it  is,  however,  always  in  relation  with 
the  diaphragm,  the  abdominal  parietes,  and  the  liver,  and  by 
a  fold  of  the  peritoneum,  called  the  g astro-splenic  omentum, 
with  the  hilus  of  the  spleen.  The  left  pneumogastric  nerve 
may  be  traced  upon  the  anterior  surface  of  the  stomach, 
and  the  right  upon  its  posterior  surface. 

The  stomach  is  to  be  removed  by  dividing  it  at  the  oesophagus, 
close  to  the  diaphragm,  and  at  the  duodenum,  in  such  a  way  as  to 
leave  behind  that  portion  perforated  by  the  ductus  choledochus  coiu- 
munis  ;  it  should  then  be  laid  open  along  the  greater  curvature. 

16* 


186  ANATOMY    OP    THE    ABDOMEN,    ETC. 

The  coats  of  the  stomach,  as  in  the  rest  of  the  alimen- 
tary canal,  are  four  in  number,  viz :  peritoneal,  muscular, 
cellular,  and  mucous.  The  peritoneal  coat  envelops  it 
entirely.  The  muscular  coat  is  made  up  of  numerous  and 
well-marked  fibres,  disposed  in  longitudinal,  circular,  and 
oblique  directions.  The  mucous  coat  is  movable,  and 
slides  upon  the  muscular,  from  which  it  is  separated  by  the 
cellular  coat ;  if  not  fully  distended  it  will  therefore  be 
thrown  into  ruga*  by  the  contraction  of  the  latter ;  its  sur- 
face is  characterized  by  a  sort  of  granulated  appearance 
due  to  the  follicles  with  which  it  is  provided.  At  the 
pyloric  extremity  the  mucous  membrane  forms  a  valve 
called  the  pylorus;  this  is  sometimes  a  complete  ring,  at 
others  merely  two  crescentic  folds ;  the  muscular  ^b 
beneath  form  a  sort  of  sphincter,  and  the  entrance  to  the 
duodenum  may  be  closed  by  their  contraction.  The  color 
and  condition  of  the  mucous  coat  is  variously  modified  by 
the  contents  of  the  stomach  and  by  post-mortem  changes. 

THE    SPLEEN. 

The  SPLEEN  is  situated  beneath  the  cartilages  of  the  ribs, 
at  the  cardiac  extremity  of  the  stomach,  with  which  it  is 
connected  by  means  of  the  gastro-splenic  omen  turn ;  it  is  also 
held  in  contact  with  the  diaphragm  by  a  suspensory  perito- 
neal ligament;  its  connections,  however,  are  not  very  strong, 
and  it  may  easily  be  torn  out  from  its  position  with  the 
fingers.  It  is  completely  invested  by  peritoneum,  which  is 
closely  adherent,  and  presents  a  smooth  surface,  convex 
externally,  and  concave  internally.  The  upper  end  of  the 
spleen  is  larger  than  the  lower ;  the  posterior  border  is 
blunt  and  rounded,  the  anterior  comparatively  sharp,  and 
containing  one  or  more  notches.  The  concavity  of  the 
spleen  admits  the  arteries,  and  gives  exit  to  the  veins, 
and  that  portion  in  relation  with* these  is  called  its  Mlus. 
The  splenic  artery,  of  large  size,  divides  at  its  entrance 
into  several  branches  ;  the  splenic  vein,  also  of  large  size,  is 
joined  by  the  gastric,  and  superior,  and  inferior  mesenteric 
veins,  and  terminates  in  the  portal  vein.  Its  nerves  are 
derived  from  the  solar  plexus. 

A  section  of  the  spleen  exhibits  a  reticulated  parenchyma 
of  very  elastic  nature,  from  the  meshes  of  which  large 
quantities  of  blood  may  be  squeezed  or  washed.  In  its 
tissue,  pearly  bodies  are  sometimes  seen,  not  unlike  miliary 
tubercles ;  these  are  called  the  corpuscles  of  the  spleen. 


THE    PANCREAS.  —  THE    LIVER.  187 

The  spleen  varies  in  weight  from  two  drachms  to  forty 
pounds ;  its  average  is  from  five  to  seven  ounces.  Its  size 
may  be  averaged  at  five  inches  in  length  by  three  or  four 
in  width,  and  one  to  two  inches  in  thickness.  Within  the 
folds  of  the  peritoneum,  in  the  neighborhood  of  this  viscus, 
it  is  not  uncommon  to  find  supplementary  spleen*,  small 
rounded  bodies,  varying  from  the  size  of  a  pea  to  that  of  a 
pigeon's  egg;  in  structure  these  are  similar  to  that  of  the 
pleen  proper. 

THE    PANCREAS. 

The  PANCREAS  is  an  irregularly  shaped  viscus,  some  six 
inches  in  length,  lying  transversely  upon  the  vertebrae, 
behind  the  stomach.  It  is  a  conglomerate  gland,  the  sub- 
stance of  which  is  of  a  pale  color,  and  broken  up  into  easily 
separated  lobules.  It  is  divided  into  a  head  and  body,  the 
head  being  that  portion  embraced  by  the  duodenum.  A 
portion  of  the  gland  surrounds  the  mesenteric  vessels,  and 
this  prolongation  is  sometimes  "called  the  lesser  pancreas. 
By  making  a  longitudinal  incision  into  the  substance  of  the 
pancreas,  and  carefully  separating  the  lobules,  a  delicate 
white  duct  will  be  exposed;  this  is  the  pancreatic  duct ; 
it  commences  at  the  extremity  of  the  gland,  and  gradually 
increasing  in  size  by  the  accession  of  small  branches,  makes 
its  exit  at  the  head  of  the  viscus,  and,  in  company  with  the 
ductus  choledochus  communis,  penetrates  obliquely  through 
the  walls  of  the  duodenum  at  the  posterior  part  of  its  per- 
pendicular portion,  opening  into  its  interior  by  a  common 
orifice  with  the  bile  duct.  Occasionally  it  has  a  separate 
aperture,  and  there  may  be  a  second,  supplementary  duct. 

THE   LIVER. 

By  lifting  the  cartilages  of  the  right  side  with  the  chain  hooks,  and 
by  lifting  and  drawing  the  liver  in  different  directions,  its  attach- 
ments and  relations  may  be  successively  observed  and  studied. 

The  LIVER  is  a  conglomerate  gland,-  and  the  largest  vis- 
cus in  the  body ;  it  weighs  from"  three  to  four  and  a-half 
pounds  ;  tys  color  is  a  reddish-brown,  and  its  surface  is 
covered  with  peritoneum,  except  in  such  intervals  as  arc 
left  between  the  layers  reflected  from  the  viscus  to  the 
parietes  of  the  abdomen,  and  which  constitute  the  liga- 
ments which  hold  it  in  place.  It  is  in  relation  superiorly 
and  anteriorly  with  the  diaphragm  and  abdominal  parietes  ; 
inferiorly  with  the  stomach  and  transverse  colon,  and  pos- 


188  AN  A  TO  MY    OF    THE    ABDOMEN,    ETC. 

teriorly  with   the   diaphragm  and  vertebral    column,  tin 
aorta,  and  vena  cava. 

The   liver  is  held  in  its   place   by  the  following  liga- 
ments : — 

Broad,  or  Suspensory,         Right  and  left  Lateral, 
Round,  Coronary. 

The  !>road,or  suspensory  ligament,  with  its  accompanying  round  liga- 
ment, was  noticed  at  the  time  the  abdomen  was  opened,  and  theii 
divided  ends  will  now  he  seen  lying  upon  the  superior  surface  of  the 
liver  at  its  anterior  margin.  It  is  a  thin,  double  layer  of  peritoneum, 
extending  from  the  posterior  to  the  anterior  border  of  the  liver,  and 
attached  to  the  diaphragm  and  anterior  wall  of  the  abdomen,  as  far  as 
the  umbilicus. 

The  round  ligament  is  a  white  fibrous  cord,  the  obliterated  umbilical 
vein  of  foetal  life,  occupying  the  lower  border  of  the  broad  ligament  ; 
it  passes  under  the  anterior  border  of  the  liver  into  a  longitudinal 
fissure  of  its  inferior  surface,  terminating  in  the  walls  of  the  portal 
vein. 

The  lateral  ligaments  are  peritoneal  folds,  passing  from  each  ex- 
tremity of  the  liver  to  the  diaphragm,  the  left  being  the  longest  of 
the  two. 

The  coronary  ligament  is  situated  along  the  posterior  border  of  the 
viscus,  between  the  two  lateral  ligaments.  The  two  reflections  of  the 
peritoneum  composing  it  leave  a  considerable  space  between  them, 
so  that  this  portion  of  the  liver  is  in  immediate  contact  with  the  dia- 
phragm, and  connected  with  it  by  firm  cellular  attachments. 

To  remove  the  liver,  these  different  ligaments  are  to  be  divided  ;  it 
is  then  to  be  carefully  dissected  from  the  diaphragm,  cutting  across 
the  vena  cava  where  it  perforates  the  muscle,  and  preserving  a  portion 
of  it  in  connection  with  the  liver.  Precaution  should  be  taken  not  to 
tear  the  liver  or  perforate  the  diaphragm,  accidents  which  are  liable 
to  occur.  The  duodenum,  or  that  portion  of  it  left  expressly  on  ac- 
count of  its  connections  with  the  liver,  should  also  be  removed  together 
with  the  ducts  which  connect  it  to  the  gall-bladder  and  inferior  sur- 
face of  the  liver. 

Removed  from  the  bod}7,  the  liver  presents  superiorly  a 
surface  uniformly  convex,  and  divided  into  two  portions 
by  the  broad  ligament,  called  right  and  left  lobes,  the 
right  being  much  the  larger  of  the  two.  It  can  now  be 
seen  that  the  posterior  border  is  rounded,  and  the  anterior 
sharp  and  thin  ;  the  posterior  border  has  a  depression  where 
it  rests  upon  the  vertebral  column  ;  the  anterior  border  is 
notched  at  the  point  of  its  separation  into  two  lobes,  and 
sometimes  also  in  front  of  the  gall-bladder. 

The  inferior  surface  of  the  liver  is  very  irregularly  con- 
cave, and  is  broken  up  by  fissures  and  lobes.  A  fissure 
containing  the  round  ligament  divides  the  under  surface, 


uci 

« 


THE    LIVER.  189 

as  the  broad  ligament  does  the  upper,  into  its  right  and  left 
lobes  ;  the  left  lobe  is  comparatively  thin  and  smooth,  the 
right  is  much  thicker;  upon  it  are  situated  three  other 
lobes,  viz. :  the  lobus  Spigelii,  caudatus,  and  quadratus. 

The  lobus  Spigelii  is  a  triangular-shaped,  partially  detached  lobe, 
surrounded  by  fissures,  and  placed  in  the  middle  of  the  posterior  part 
of  the  liver. 

The  lobus  caudatus  is  a  sort  of  ridge,  extending  from  the  lobus 
Spigelii  toward  the  middle  of  the  right  lobe ;  it  is  not  usually  well 
defined. 

The   lobus   quadratus  is  the  portion  of  the  right  lobe  intervening 
between  the  gall-bladder  and  the  fissure  of  the  round  ligament,  and 
front  of  the  fissure  at  which  enter  the  portal  vein  and  hepatic 
ery. 

The  transverse,  fissure  is  the  most  important  of  all  the  fissures  of 
the  under  surface  of  the  liver  ;  it  occupies  nearly  the  centre  of  the 
organ,  and  is  the  depression  where  the  portal  vein  and  hepatic  artery 
enter,  and  the  hepatic  duct  makes  its  exit.  It  is  sometimes  called 
the  hilus,  and  as  being  the  entrance  or  porta  of  the  liver,  gives  a 
name  to  the  vein  which  finds  admission  at  this  point.  The  hepatic 
duct  is  the  most  anterior  of  the  vessels  of  the  transverse  fissure,  the 
artery  is  placed  next,  while  the  vena  portse  is  the  most  posterior. 

The  longitudinal  .fissure,  containing  the  round  ligament,  joins  the 
transverse  nearly  at  a  right  angle  ;  the  substance  of  the  liver  some- 
times crosses  this  fissure,  and  converts  it  partially  into  a  canal. 

'Fhejissure  of  the  ductus  i^enosus  is  that  portion  of  the  longitudinal 
fissure  posterior  to  the  transverse;  it  lies  between  the  lobus  Spigelii 
and  the  left  lobe,  and  contains  a  rounded  cord,  continuous  with  the 
round  ligament,  which  terminates  in  the  vena  cava  ;  this  cord  being 
the  obliterated  ductus  venosus,  which,  during  foetal  life,  conveys 
directly  to  the  vena  cava  a  portion  of  the  blood  of  the  umbilical 
vein. 

The  fissure  of  the  vena  cava  lies  between  the  lobus  SpigeJii  and  the 
right  lobe  ;  it  is  occupied  by  the  vena  cava,  and  is  sometimes  con- 
verted into  a  canal.  On  laying  open  the  vena  cava,  the  orifices  of  the 
hepatic  reins  will  be  seen,  this  being  the  point  at  which  they  discharge 
thfir  blood  into  the  general  venous  circulation. 

Thejinure  of  the  gall-bladder  is  the  fossa  in  which  that  receptacle 
rests. 

From  the  preceding  description,  it  will  be  seen  that  the 
liver  has  five  lobes,  five  fissures,  five  ligaments,  and  five 
vessels,  which  may  thus  be  tabulated: — 

Lobes.  Fissures.  Vessels.  Ligaments. 

Right,         Transverse,          Hepatic  Duct,     Coronary, 
Left,  Longitudinal,      Hepatic  Arter3r,  Broad, 

Spigelii,      Ductus  Yenosns,  Hepatic  Veins,    Right  Lateral, 
C  mid  at  us,  Vena  Cava,          Portal  Vein,       Left  Lateral, 
Qoadratus.  Gall-Bladder.       Vena  Cava.         Round. 


190 


ANATOMY     OF     THE     ABDOMEN,    ETC. 


The  GALL-BLADDER  is  a  pyriform  sac,  the  fund  us 
which  extends  just  beyond  the  anterior  margin  of  the  liver; 
the  neck  is  directed  toward  the  transverse  fissure,  and  tei 
minates  in  the  cystic  duct.     The  coats  of  the  gall-bladd< 
are  three  in  number,  viz.,  peritoneal,  cellular,  and  mucous 
The  peritoneal  coat  only  partially  invests  it,  the  posteri< 
surface  being  in  direct  contact  with  the  liver,  and  connectec 
to  it  by  the  cellular  coat.     The  mucous  coat  is  very  fineb 
reticulated,  and  stained  deep  brown  by  the  bile  which  tinge* 
all  the  coats,  and  gives  the  bladder  a  greenish  hue ;  to  ware 
the  neck,  the  mucous  membrane  is  thrown  into  prominent 
folds,  which  form  a  sort  of  valve  at  the  point  of  its  uuioi 
with  the  cystic  duct. 

The  cystic  duct,  about  an  inch  in  length,  joins  the  hepatic 
duct  of  the  liver  two  inches  distant  from  the  trans ven 
fissure  at  which  it  emerges ;  their  union  forms  the  ducti 
choledochus   communis,  a   tube  of  some  three   inches    11 
length,  which  terminates  in  the  duodenum  as  already  d< 
scribed.     The  gall-bladder  is  merely  a  reservoir  of  supei 
fluous  bile,  and  the  duct  us  choledochus  conveys  the  bih 
from  it  as  well  as  that  derived  directly  from  the  liver. 

The  hepatic  duct,  the  hepatic  artery,  and  portal  vein,  a] 
surrounded  by  a  loose  areolar  tissue  which  accompani< 
them   in  their  ramifications,  and  which  is  called  Glissonh 
capsule.    This  capsule  may  be  seen,  constituting,  as  it  wen 
the  fibrous  skeleton  of  the  organ,  by  tearing  the  liver, 
by  stripping  off  the  closely  adherent  peritoneal  coat ; 
surrounds  the  minute  granules  or  acini,  of  which  this  fn 
ture  shows  the  liver  to  be  made  up. 

The  hepatic  veins  are  closely  adherent  by  their  pariel 
to  the  substance  of  the  liver,  and  cannot,  therefore,  coi 
tract,  as  the  loose  areolar  tissue  surrounding  the  ports 
veins  permits  those  vessels  to  do ;  in  a  section  of  the  livei 
consequently,  these  may  be  easily  distinguished  from  eacl 
other.  The  portal  vein  will  be  found  collapsed,  and  accon 
panied  by  an  artery  and  a  duct ;  while  the  hepatic  vein  wil 
remain  open  and  uncontracted,  and  is  unaccompanied  bj 
any  other  vessel. 

The  liver  is  supplied  with  blood  from  the  hepatic  brand 
of  the  coeliac  axis ;  the  portal  vein  also  conveys  its  current 
through  the  organ,  and,  collecting  the  impure  blood  of  the 
hepatic  arteries,  terminates  in  the  hepatic  vein  ;  this  empth 
into  the  vena  cava  inferior,  and  so  completes  the  hepati< 
circulation.  The  hepatic  plexus  of  nerves,  derived  f'roi 


THE    KIDNEYS.  191 

the  solar  plexus,  accompanies  the  hepatic  artery  in  its  sub- 
divisions. The  liver  also  receives  branches  from  the  phre- 
nic and  pneumogastric  nerves. 


, 


DISSECTION  IV. 

THE    SUPRA-RENAL   CAPSULES. 


The  supra-renal  capsules  are  to  be  sought  for  beneath  the  perito- 
um,  high  up  in  the  lumbar  region,  on  each   side   of  the  spinal 
column. 

The  SUPRA-RENAL  CAPSULES  are  small,  flat,  crescentic 
bodies,  covered  in  by  peritoneum  and  surmounting  the  kid- 
neys, to  which  their  concave  surface  is  sometimes  directly 
applied ;  an  interval  not  unfrequently,  however,  exists 
between  the  two  organs.  They  are  of  a  yellowish  color, 
and  easily  obscured  among  the  fat  and  cellular  tissue  of 
the  surrounding  parts.  The  right  capsule  rests  upon  the 
diaphragm  between  the  kidney  and  the  liver,  oftentimes 
as  closely  adherent  to  one  as  the  other  of  these  organs. 
The  left  capsule  also  rests  upon  the  diaphragm,  beneath 
the  pancreas  and  spleen.  For  so  small  organs  they  are 
largely  supplied  both  with  nerves  and  arteries,  the  former 
constituting  a  supra-renal  plexus  derived  from  the  solar 
plexus,  the  latter  being  branches  of  the  aorta,  and  the 
phrenic  and  renal  arteries ;  the  supra-renal  vein  terminates 
sometimes  in  the  inferior  cava  and  sometimes  in  the  renal 
vein.  Upon  section,  they  are  seen  to  be  made  up  of  an 
external  or  cortical  substance,  of  a  yellow  color,  and  an 
internal  or  medullary  substance,  dark  and  semi-fluid  ;  an 
internal  cavity  is  sometimes  described,  but  it  is  a  question 
if  it  be  not  the  result  of  post-mortem  degeneration.  One 
or  two  instances  of  entire  absence  of  the  supra-renal 
capsules  have  been  reported,  and  in  the  foetus  they  have 
been  found  fused  into  one  body  across  the  vertebral  column. 

THE    KIDNEYS. 

The  kidneys  occupy  the  lumbar  region  on  each  side  of  the  verte- 
bral column,  lying  beneath  the  peritoneum,  enveloped  in  fat  and 
cellular  tissue.  To  expose  them,  both  the  peritoneum  and  lumbar 
fascia  must  be  removed,  and  the  ureter  should  be  traced  downward, 
either  in  part  or  the  whole  of  its  course. 


192  ANATOMY    OF    THE    ABDOMEN,    ETC. 

The  KIDNEYS  are  oval-shaped  organs  of  a  deep  red  color, 
and  smooth  surface,  convex  externally  and  concave  toward 
the  vertebral  column ;  the  concave  border  at  its  central 
part  presents  a  longitudinal  fissure  called  the  hilus ;  at  this 
point  the  renal  artery  enters  and  the  vein  and  ureter 
emerge. 

The  URETER  is  the  excretory  duct  which  conveys  the 
urine  to  the  bladder ;  it  is  of  the  size  of  a  pipe-stem,  except 
at  its  commencement,  where  it  is  dilated  and  forms  part 
of  what  is  called  the  pelvis  of  the  kidney.  It  is  of  a 
bluish-white  color  and  of  a  firm  fibrous  texture,  and  is 
lined  within  by  a  thin  mucous  membrane ;  it  passes  down- 
ward upon  the  psoas  muscle,  behind  the  peritoneum, 
crosses  the  external  or  common  iliac  artery,  and  dips  down 
behind  the  bladder  to  enter  it  at  its  base.  The  ureter  is 
sometimes  double,  either  in  a  part  or  the  whole  of  its 
length. 

The  ureter  should  be  divided  midway  between  the  kidney  and  the 
Madder;  then  the  vein  and  artery  being  cut  across,  the  kidney  may 
be  easily,  and  without  injury,  torn  from  its  bed  by  the  fingers.  A 
longitudinal  incision  along  its  convex  margin  should  divide  the 
kidney  in  such  a  way  that  it  may  be  opened  and  its  interior  exposed, 
without  its  two  halves  being  separated  at  the  concave  border. 

The  kidney  is  about  four  inches  long,  two  wide,  and  on< 
in  thickness ;  it  weighs  about  four  and  a  half  ounces.  Its 
upper  extremit}^  is  larger  than  the  lower;  its  postcrioi 
surface  is  flatter  than  its  anterior,  and  it  is  invested  with  a 
special  capsule,  which  the  nail  of  the  thumb  and  fore-fingei 
may  easily  detach  from  its  surface.  Internally,  it  is  com- 
posed of  two  distinct  structures  and  an  irregular-shaped 
cavity,  called  the  pelvis.  That  portion  surrounding  the 
pelvis  is  made  up  of  cones,  six  or  eight  in  number,  called 
pyramids  of  Malpiglii,  the  apices  of  which  are  directed 
toward  the  centre  of  the  organ ;  they  are  composed  of 
congeries  of  straight  tubes  called  tubuli  uriniferi.  The 
apices  of  the  pyramids  are  called  papillae,  and  are  covered 
by  a  thin  mucous  membrane,  perforated  by  orifices,  through 
which  the  tubuli  discharge  the  urinary  secretion  into  the 
pelvis;  they  are  surrounded  by  a  sort  of  "prepuce,"  so  to 
speak,  also  covered  by  a  thin  mucous  membrane,  and  which 
is  called  the  calyx,  or  infundibulum,  of  the  pyramid ;  the 
projection  of  the  papillae  into  the  pelvis  produces  the  irregu- 
larity of  outline  which  characterizes  that  cavity ;  the  ureter 


THE    DIAPHRAGM.  193 

opens  from  the  general  cavity  of  the  pelvis,  and  their 
mucous  surfaces  are  continuous.  The  external,  or  cortical 
portion  of  the  kidney,  surrounds  the  bases  of  the  pyramids, 
and  penetrates  irregularly  between  them  under  the  name  of 
the  columns  of  Bertin;  it  is  composed  of  the  tubuli  con- 
voluted among  minute  vascular  ramifications. 

The  kidney  is  a  very  vascular  organ  and  receives  its  blood 
through  the  renal  artery,  a  large  branch  of  the  aorta, 
affording  an  excellent  illustration  of  the  law  that  the  size 
of  an  artery  is  in  proportion,  not  to  the  size  of  the  viscus 
which  it  is  distributed,  but  to  the  activity  of  its  func- 
>ns.  The  renal  vein  empties  into  the  inferior  vena  cava ; 
id  the  nerves,  which  are  abundant,  are  received  from  the 
Mini  plexus,  this  being  derived  from  the  solar  plexus  and 
lesser  splanchnic  nerve.  The  large  upper  extremity, 
flattened  posterior  surface,  together  with  the  relative 
*ition  of  the  vessels  at  the  hilus  permit  the  right  kidney 
be  distinguished  from  the  left  after  their  removal  from 
e  body ;  the  renal  vein  is  the  most  anterior,  the  artery 
is  behind  the' vein,  and  the  ureter  posterior  to  them  both. 

The  kidneys  not  unfrequently  present  deviations  from 
their  normal  shape  and  position  ;  sometimes  they  are  united 
into  one  body  across  the  vertebral  column,  forming  what 
is  called  a  horse-shoe  kidney ;  occasionally  one  is  wanting. 
They  may  be  found  placed  much  lower  in  the  lumbar 
region  than  usual,  and  have  even  been  found  in  the  pelvis. 
They  are  usually  firmly  fixed  in  their  positions,  but  in 
certain  instances  a  degree  of  mobility  has  been  noticed, 
appreciable  by  palpation  during  life,  and  constituting  what 
is  called  a  floating  kidney. 

THE    DIAPHRAGM. 

To  get  a  good  view  of  the  diaphragm,  a  large  block  is  to  be  placed 
under  the  loins  in  such  a  way  as  to  elevate  the  base  of  the  thorax. 
The  peritoneum  must  be  thoroughly  removed  from  its  surface;  and  if 
the  thorax  has  not  yet  been  opened,  it  can  be  readily  stripped  off  by 
the  forceps  and  fingers. 

The  DIAPHRAGM  is  a  muscular  plane  separating  the  abdo- 
men from  the  thorax;  it  arises  from  the  sternum  by  short 
and  separated  fibres,  which  leave  a  triangular  interval 
between  them,  covered  only  by  the  peritoneum  on  one  side 
and  the  pleura  on  the  other ;  from  the  superior  border  and 
internal  surface  of  the  last  six  ribs  by  serrations  which 
IT 


194 


ANATOMY  OF  THE  ABDOMEN, ETC 


indigitate  with  the  transversalis  muscle  of  the  abdomei 
(p.  166);  also  from  a  fibrous  arch  called  the  ligamentw 
arcuatum  externum,  extending  from  the  tip  of  the  last  rib 
to  the  transverse  process  of  the  first  lumbar  vertebra,  and 
curving  over  the  quadratus  lumborum  muscle ;  it  further 
arises  from  a  smaller  fibrous  arch  called  the  ligamentum 
arcuatum  internum,  which  stretches  from  the  termination 
of  the  preceding  to  the  body  of  the  second  lumbar  vertebra, 
curving  over  the  psoas  magnus  muscle;  and  also  from  the 
bodies  of  the  second  and  third  lumbar  vertebrae  by  tendin- 
ous fibres  which  are  common  to  it  and  the  anterior  common 
ligament  of  the  vertebrae.  From  this  circumference  the 
fibres  converge  to  be  inserted  into  the  central  tendon,  a 
glistening  expansion  in  the  centre  of  the  muscle,  the 
metallic  brilliancy  of  which  has  given  it  the  name  of 
speculum  of  Van  Helmont.  The  above  description  is  of 
what  is  called  the  larger  muscle  of  the  diaphragm.  The 
lesser  muscle  consists  of  two  fleshy  bundles  arising  by 
separate  tendons  from  the  lumbar  vertebrae  j  the  right  is 
the  larger  and  the  longer ;  it  is  connected  with  the  bodies 
and  intervertebral  cartilages  of  the  upper  four  lumbar 
vertebras ;  the  left  bundle  takes  its  origin  from  only  the 
upper  three ;  both  are  inserted  into  the  central  tendon. 
These  tendons  are  also  called  the  pillars  or  crara  of  the 
diaphragm,  and  the  left  one  is  sometimes  wanting.  The 
right  pillar  crosses  the  left  pillar  in  such  a  way  as  to  divide 
the  interval  between  them  into  two  separate  parts ;  the 
lower,  parabolic  in  shape,  gives  passage  to  the  aorta,  vena 
azygos,  and  thoracic  duct ;  the  upper,  elliptical  in  shape, 
transmits  the  oesophagus  and  the  pneumogastric  nerves. 
In  the  central  tendon  is  a  third  opening,  the  largest  of  all, 
which  transmits  the  vena  cava  inferior. 

The  diaphragm,  on  the  thoracic  side,  is  covered  by  the 
pleura  and  the  pericardium,  the  fibrous  layer  of  which 
blends  with  the  central  tendon. 

The  diaphragm  is  supplied  by  the  phrenic  nerves,  and  is 
nourished  by  the  phrenic  arteries  and  by  the  musculo- 
phrenic  branch  of  the  internal  mammary  artery. 

The  RECEPTACULUM  CHYLI,  ordinarily  the  commencement 
of  the  thoracic  duct  (p.  123),  lies  close  beside  the  right 
pillar  of  the  diaphragm,  and  between  the  aorta  and  vena 
cava ;  it  usually  rests  upon  the  second  lumbar  vertebra, 
and  consists  of  a  thin,  semi-transparent,  membranous  sac, 


SUPERFICIAL    FEMORAL    REGION.  195 

oblong  and  irregularly  shaped ;  it  is  usually  empty,  and 
may  be  best  demonstrated  by  insufflation  with  the  blow- 
pipe from  the  duct  above.  The  thoracic  duct  may  some- 
times, though  rarely,  be  traced  below  the  receptaculum, 
which,  in  that  case,  becomes  merely  a  dilated  portion  of 
the  duct. 

1  The  greater  and  lesser  vena  azygos  (p.  123)  may  some- 
times be  better  seen  in  this  connection  than  at  any  other 
period  of  the  dissection.  Both  these  veins  usually  pass 
through  the  aortic  opening  of  the  diaphragm,  but  they  not 
unfrequently  perforate  its  fibres  at  the  side  of  the  pillars. 

SUPERFICIAL   FEMORAL   REGION. 

The  knees  of  both  legs  should  be  bent  so  as  to  bring  the  soles  of  the 
feet  in  apposition,  with  the  heels  approached  to  the  nates  ;  an  inci- 
sion, six  inches  in  length,  is  to  be  made  through  the  skin  from  the 
iiitre  of  Ponpart's  ligament  down  the  thigh,  and  the  integument 
jflected  to  either  side ;  this  will  expose  the  superficial  fascia. 

The  superficial  fascia  of  the  thigh,  like  that  of  the  abdo- 
ien,  with  which  it  is  continuous,  consists  of  two  layers ; 

contains  several  small  arterial  branches,  all  arising  from 
te  femoral  artery  just  below  Poupart's  ligament. 

The  superficial  epigastric  artery  passes  upward,  between  the  two 
layers  of  the  fascia,  toward  the  umbilicus,  and  has  already  been  seen, 
in  part,  during  the  dissection  of  inguinal  hernia. 

The  superficial  external  circumflex  artery  passes  outward  toward  the 
anterior  superior  spinous  process  and  crest  of  the  ilium. 

The  superficial  external  pudic  artery  passes  inward  to  be  distributed 
to  the  integument  of  the  penis  and  scrotum,  or  to  the  labia  niajora  iu 
the  female* 

Several  cutaneous  nerves  will  be  found  lying  in  the  super- 
ficial fascia  ;  they  are  small,  and  derived  from  the  anterior 
crural  and  genito-crural  branches  of  the  lumbar  plexus.. 

Enlarged  lymphatic  glands  are  usually  found  both  in 
and  beneath  the  superficial  fascia;  they  are  connected  with 
the  lymphatics  of  the  lower  extremity,  and  their  efferent 
ducts  enter  the  abdomen  through  the  sapheuous  opening. 

The  superficial  fascia  may  be  removed  by  dissecting  it  away  from 
the  fascia  lata  beneath  ;  a  portion  of  it  should,  however,  be  left  for  the 
present,  around  the  point  where  the  saphena  vein  penetrates  the  thigh. 

The  deep  external  pudic  artery,  arising  from  the  femoral, 
lies  between  the  superficial  and  the  deep  fascia;  after  a 
short  course  toward  the  inside  of  the  thigh  it  penetrates 


196  ANATOMY    OF    THE    ABDOMEN,    ETC. 

the  deep  fascia,  and  then,  reappearing  from  beneath  it,  is 
distributed  to  the  external  organs  of  generation.  It  is  tin 
largest  of  the  superficial  arteries. 

ANATOMY  OF  FEMORAL  HERNIA. 

Inasmuch  as  the  dissection  of  the  internal  abdominal  muscles,  and 
the  parts  in  relation  to  them,  will  destroy  many  of  those  connected 
with  the  anatomy  of  femoral  hernia,  it  is  desirable  to  proceed  to  il 
examination  before  they  are  disturbed.     Femoral  hernia  is  most  ad- 
vantageously studied  upon  a  female  subject. 

The  INTERNAL  SAPHENA  VEIN,  commencing  on  the  back 
of  the  foot,  ascends  along  the  inside  of  the  thigh  to  join 
the  femoral  vein ;  that  part  of  it  exposed  in  the  present 
dissection,  lies  between  the  superficial  and  the  deep  fascia, 
and  receives  several  small  veins  from  the  neighborhood ; 
it  passes  through  an  opening  in  the  deep  fascia,  called  the 
saphenous  opening,  and  then  unites  with  the  femoral  vein. 
It  is  at  this  opening  that  femoral,  or,  as  it  is  sometimes 
called,  crural  hernia,  takes  place.  A  portion  of  the  super- 
ficial fascia,  perforated  by  small  orifices,  which  give  en- 
trance to  the  efferent  ducts  of  the  lymphatic  glands  im- 
bedded in  it,  and  hence  called  the  cribriform  fascia,  covers 
in  the  saphenous  opening. 

The  deep  fascia,  or  fascia  lata,  is  a  strong  fibrous  sheath 
investing  the  whole  lower  extremity.  The  saphenous  open- 
ing, a  little  to  the  inside  of  the  middle  of  the  thigh,  and  an 
inch  below  Poupart's  ligament,  ovoid  in  shape,  and  in  out- 
line resembling  the  reversed  Greek  letter  sigma,  divides  the 
fascia  lata  into  two  parts,  iliac  and  pubic.  The  iliac  por- 
tion is  on  the  outer  side,  and  is  connected  with  the  whole 
length  of  Poupart's  ligament ;  from  this  attachment  it 
passes  outward  and  downward,  its  edge  forming  the  outer 
margin  of  the  saphenous  opening,  and  constituting  what  is 
called  its  falciform  border.  This  border  may  be  followed 
round,  underneath  the  saphena  vein,  and  will  be  found  to 
unite  with  the  pubic  portion  of  the  fascia  lata  on  the  inside 
of  the  opening ;  it  also  blends  with  the  superficial  fascia, 
so  that  they  are  only  separable  by  the  knife.  The  pubic 
portion  of  the  fascia  lata  is  inserted  into  the  spine  of  the 
os  pubis,  and  into  the  pectineal  line,  where  it  becomes 
continuous  with  the  fascia  investing  the  psoas  and  iliacus 
muscles  within  the  abdomen.  Poupart's  ligament,  attached 
to  the  spine  of  the  os  pubis,  also  extends  inward  three- 
fourths  of  an  inch,  forming  a  triangular  expansion  inserted 


a 


ANATOMY    OP    FEMORAL     HERNIA.  19t 

into  the  pectineal  line  and  having  a  concave  border  directed 
toward  the  femoral  vessels.  This  triangular  portion  is 
known  as  Gimbernatfs  ligament.  A  portion  of  the  fascia 
luta  blends  with  this  under  the  name  of  Hey's  ligament. 

Reverting  to  the  abdominal  cavity,  and  removing  the 
peritoneum,  it  will  be  seen  that  the  transversalis  fascia 
(p.  169),  and  the  fascia  covering  the  psoas  and  iliacus  mus- 
cles unite,  externally  to  the  femoral  vessels,  and  form  a 
continuous  fold,  closely  connected  with  Poupart's  liga- 
ment ;  where  the  vessels  pass  out  these  fasciae  separate 
and  surround  them,  and  blend  with  their  areolar  sheath 
about  two  inches  below  the  ligament ;  the  sort  of  funnel 
thus  made,  and  through  which  the  vessels  pass  downward 
into  the  thigh,  is  called  the  infundibuliform  fascia.  It  is 
lain,  therefore,  that  while  the  fold  protects  »the  crural 
arch,  which  is  the  space  between  Poupart's  ligament  and 
the  os  innominatum,  from  a  hernial  protrusion  externally, 
it  is  liable  to  occur  internally  where  the  exit  of  the  vessels 
obliges  these  fasciae  to  separate. 

The  crural  arch  is  occupied,  externally,  by  the  psoas  and 
iliacus  muscles,  between  which  passes  the  crural  nerve ;  next 
the  muscles  comes  the  external  iliac  artery,  then  the  external 
iliac  vein,  between  which  and  the  inner  termination  of  Pou- 
part's ligament  is  a  space  called  the  crural  ring.  The  crural 
ring  is  about  half  an  inch  wide,  and  is  filled  with  the  sub- 
peritoneal  cellular  tissue ;  that  portion  of  this  tissue  which 
stretches  over  the  crural  ring,  and  in  which  there  is  often 
found  a  lymphatic  gland,  is  called  the  septum  crurale. 
The  greater  size  of  the  crural  arch  in  females  than  in 
males,  owing  to  the  greater  breadth  of  their  pelvis  and  the 
lesser  development  of  the  soft  parts,  makes  the  crural 
ring  a  much  larger  space  in  them,  and  explains  why  they 
are  more  subject  than  males  to  hernia  at  this  point.  The 
vessels  and  the  crural  ring  are  all  inclosed  in  the  infundi- 
buliform fascia,  but  are  separated  from  each  other  by  septa. 
By  dividing  Poupart's  ligament,  and  turning  it  carefully 
to  either  side,  these  septa  may  be  seen,  one  between  the 
artery  and  vein,  and  one  between  the  vein  and  the  crural 
ring.  The  space  between  the  crural  ring  and  the  point  at 
which  the  saphena  vein  joins  the  femoral,  is  called  the 
('rural  canal ;  its  anterior  wall  is  the  transversalis  portion 
of  the  infundibuliform  fascia,  with  the  falciform  border  of 
the  iliac  side  of  the  fascia  lata  ;  the  posterior  wall  is  formed 

IT* 


198 


ANATOMY    OF    THE    ABDOMEN,    ETC. 


by  the  iliac  portion  of  the  infundibuliform  fascia  and  part 
of  the  pubic  side  of  the  fascia  lata  ;  its  external  wall  is  the 
septum,  forming  the  division  between  the  canal  and  the 
vein,  and  its  internal  wall,  Gimbernat's  and  Hey's  liga- 
ment, covered  with  their  portion  of  the  infundibuliform 
fascia.  The  epigastric  artery  is  in  close  relation  to  the 
upper  and  outer  side  of  the  crural  ring,  and  the  obturator 
artery,  when  given  off  from  the  external  iliac,  dips  down- 
ward along  its  outer  and  inferior  edge ;  in  a  certain  num- 
ber of  instances  this  artery  arises  from  a  trunk  common  to 
it  and  the  epigastric,  in  which  case  it  curves  around  the 
ring  to  descend  upon  its  inner  side ;  the  obturator  vein 
may  follow  the  same  course.  It  will  be  seen  that  this  dis- 
tribution of  the  artery  exposes  it  to  be  wounded  in  dividing 
the  crural  ring,  in  an  operation  for  strangulated  femoral 
hernia ;  observation,  however,  having  shown  that  the  point 
of  constriction  is  ordinarly  in  the  fascia  lata  and  not  in  the 
ring,  the  danger,  which  formerly  was  so  properly  dreaded, 
has  disappeared  before  a  more  enlightened  practice. 

The  spermatic  cord  is  separated  from  the  crural  ring  by 
Poupart's  ligament. 

The  preceding  description  shows  that  a  knuckle  of  intes- 
tine, entering  the  crural  ring,  finds  little  or  nothing  to 
oppose  its  protrusion  at  the  saphenous  opening,  externally  ; 
and  although  while  in  the  canal  it  must  be  much  constricted, 
from  the  unyielding  nature  of  its  walls,  the  hernia  may, 
after  emerging,  expand  into  a  tumor  of  considerable  size. 
The  blending  of  the  superficial  fascia  with  the  fascia  lata, 
just  below  the  saphenous  opening,  prevents  the  hernia  from 
descending  below  that  point,  and  arrived  at  this  obstruction, 
it  turns  upward  toward  Poupart's  ligament.  The  practical 
importance  of  this  fact,  in  connection  with  attempts  at 
reduction  by  taxis,  is  of  course  obvious ;  to  return  the 
hernia  within  the  abdominal  cavity,  pressure  must  first  be 
exerted  downward,  then  backward  and  upward. 

The  intestine,  in  descending,  must  carry  before  it  the 
following  coverings  ;  first,  the  peritoneum,  then  the  septum 
cm  rale,  and  that  portion  of  the  infundibuliform  fascia 
which,  forming  the  anterior  wall  of  the  canal,  is  perforated 
by  the  saphena  vein,  these  two  latter  constituting  what  is 
called  the  fascia  propria  of  the  hernia ;  and,  externally 
to  the  saphenous  opening,  the  cribriform  fascia,  the  superfi- 
cial fascia,  and  the  integument. 


THE    LUMBAR    PLEXUS.  199 


THE    LUMBAR   PLEXUS. 

The  dissection  of  the  lumbar  plexus  presupposes  the  removal  of  the 
peritoneum  and  cellular  tissue  in  the  lumbar  region  ;  the  nerves 
composing  it-  are  mostly  small  in  size,  and  though  liable  to  be  divided 
in  the  dissections  already  made,  their  origin  and  a  portion  of  their 

urse  may  always  be  demonstrated. 


The  LUMBAR  PLEXUS  is  formed  by  the  communications 
of  the  anterior  branches  of  the  five  lumbar  nerves ;  the 

rterior  branches  being  distributed  to  the  muscles  of  the 
k.     The  principal  trunks  are  the  following,  viz : — 
Musculo-cutaneous,  Crural, 

External  Cutaneous,  Obturator, 

Genito-crural,  Lumbo-sacral. 

The  mnsculo-cutaneous  nerve,  coming  from  the  first  lumbar  nerve, 
crosses  the  quadratus  lumborum  muscle  obliquely,  to  reach  the  mid- 
dle of  the  crest  of  the  ilium,  where  it  pierces  the  transversalis  muscle, 
and  divides  into  two  branches,  the  abdominal  and  the  scrotal ;  the 
hduminal  supplying  the  muscles  and  integument  of  the  abdomen  ; 
scrotal,  joining  the  spermatic  cord  in  the  male,  and  the  round 
gament  in  the  female,  at  the  external  inguinal  ring,  is  distributed 

the  integument  of  the  scrotum,  or,  in  the  female,  to-  the  labia 
ajora. 

The  external  cutaneous  nerve,  coming  from  the  second  lumbar  nerve, 
crosses  the  iliacus  interims  muscle  obliquely,  to  reach  the  anterior 
superior  spinous  process  of  the  ilium,  where  it  passes  underneath 
Toupart's  ligament,  and  is  distributed  to  the  integument  of  the  gluteal 
region,  and  the  outside  of  the  thigh. 

The  genito-crural  nerve,  coming  from  the  second  and  third  lumbar 
nerves,  runs  down  upon  the  psoas  muscle,  and  divides  into  a  genital 
and  crural  branch.  The  genital  branch  enters  the  internal  abdominal 
ring,  and  accompanies  the  spermatic  cord,  or  round  ligament,  to  the 
integument  of  the  groin ;  the  crural  descends  along  the  outer  border 
of  tiie  external  iliac  artery,  enters  the  sheath  of  the  femoral  vessels, 
and  is  distributed  to  the  integument  of  the  front  of  the  thigh. 

The  crural  nerve,  coming  from  the  second,  third,  and  fourth  lumbar 
nerves,  is  the  largest  branch  of  the  lumbar  plexus  ;  it  pierces  the 
psoas  muscle,  then  passes  downward  between  it  and  the  iliacus 
internus  muscle,  and,  about  an  inch  below  Poupart's  ligament,  divides 
into  numerous  branches  hereafter  to  be  described,  (p.  223.) 

The  obturator  nerre,  coming  from  the  third  and  fourth  lumbar  nerves, 
pisses  down  among  the  fibres  of  the  psoas  muscle,  and  behind  the  iliac 
vessels,  along  the  brim  of  the  pelvis  to  the  upper  and  inner  part  of 
the  obturator  foramen,  which  it  perforates,  to  be  distributed  to  the 
adductor  muscles  of  the  thigh.  An  accessory  obturator  branch  some- 
times arises  by  separate  filaments  from  the  third  and  fourth  lumbar 
nerves,  or  from  the  upper  part  of  the  obturator  nerve  itself;  it  passes 
down  along  the  inner  border  of  the  psoas  muscle,  and  is  interesting 
only  because  it  supplies  the  hip-joint,  which  it  enters  beneath  the 


200  ANATOMY     OF    THE    ABDOMEN,    ETC, 


transverse  ligament,  in  company  witli  the  articular  branch  of  the 
internal  circumflex  artery.  When  the  accessory  nerve  is  wanting, 
the  hip-joint  is  supplied  by  a  branch  of  the  obturator  nerve, 

The  lumbo-sacral  nerve,  from  the  fourth  and  fifth  lumbar  nerve 
descends  into  the  pelvis  over  the  base  of  the  sacrum,  and  unites  tl 
lumbar  with  the  sacral  plexus. 

The  dissection  of  these  nerves  will  have  exposed  the  in- 
ternal abdominal  muscles. 

The  QUADRATUS  LUMBORUM  is  covered  in  by  the  anteri< 
layer  of  the  lumbar  fascia ;  this  being  removed,  it  will 
found  to  arise  from  the  last  rib,  and  the  transverse  pi 
cesses  of  the  upper  four  lumbar  vertebrae,  and  to 
inserted  into  the  posterior  part  of  the  crest  of  the  ilium. 
If  the  muscle  is  divided,  and  the  two  ends  reflected,  the 
middle  portion  of  the  lumbar  fascia  will  be  exposed. 

The  PSOAS  PARVUS  MUSCLE  lies  in  front  of  and  upon  the 
psoas  magnus ;  it  arises  from  the  sides  of  the  bodies  of  the 
last  dorsal  and  first  lumbar  vertebrae,  forming  a  small  belly 
which  expands  into  a  broad,  flat  tendon,  which,  losing 
itself  in  the  fascia  of  the  iliacus  muscle,  is  inserted  into 
the  pectineal  line  and  ilio-pectineal  eminence  in  a  manner 
calculated  to  prevent  the  contractions  of  the  psoas  magnus 
muscle  from  compressing  the  iliac  vessels.  This  muscle  is 
frequently  wanting;  when  absent  the  fascia  iliaca  is  more 
developed,  and  supplies  its  place. 

The  PSOAS  MAGNUS  MUSCLE  is  a  long  muscle,  lying- 
parallel  to  the  vertebral  column,  and  arising  from  the  sides 
of  the  bodies  of  the  last  dorsal,  and  four  upper  lumbar 
vertebrae,  and  from  the  transverse  processes  of  all  the 
lumbar  vertebrae;  it  forms  the  border  of  the  true  pelvis 
laterally,  and  is  inserted,  in  common  with  the  iliacus 
internus  muscle,  into  the  trochanter  minor  of  the  femur, 
and  an  inch  or  more  of  the  shaft  of  the  bone  below  it. 
That  portion  arising  from  the  transverse  processes  is  some- 
times distinct  from  the  rest  of  the  muscle  in  its  whole 
course. 

The  ILIACUS  INTERNUS  MUSCLE  arises  from  the  transverse 
process  of  the  last  lumbar  vertebra,  the  crest  and  concavity 
of  the  ilium,  and  the  anterior  part  of  the  capsule  of  the 
hip-joint,  and  in  common  with  the  tendon  of  the  psoas 
magnus,  is  inserted  into  the  lesser  trochanter  of  the  femur. 
The  insertions  of  neither  of  these  muscles  can  be  satis- 
factorily seen  until  after  the  dissection  of  the  muscles  of 
the  anterior  femoral  region. 


ANATOMY    OF    THE    PERINEUM.  201 

The  EXTERNAL  ILIAC  ARTERY,  with  its  accompanying 
vein,  lies  along  the  inner  border  of  the  psoas  muscle ;  it 
has  no  branches  till  it  reaches  Poupart's  ligament,  where 
it  gives  off  two,  and  sometimes  three.  About  half  an  inch 
outside  the  artery  as  it  passes  under  Poupart's  ligament, 
the  crural  nerve  may  be  seen,  lying  deep  between  the  psoas 
and  iliacus  muscles. 

The  epigastric  artery  has  been  already  noticed  (p.  167),  but  may 
now  be  more  particularly  observed  as  to  its  origin  from  the  external 
iliac ;  this  is  usually  close  to  Poupart's  ligament,  but  it  may  be  found 
at  a  very  considerable  distance  either  above  or  below  it ;  it  frequently 
furnishes  the  obturator  artery. 

The  circAimflexa  iJii  artery  arises  from  the  outer  side  of  the  artery, 

and  winds  along  Poupart's  ligament,  and  the  crest  of  the  ilium  ;  it 

ies    between   the   internal    oblique   and    transversalis  muscles,  and 

reaks  up  into  numerous  branches,  some  of  which  supply  the  muscles, 

while  others  inosculate  with  the  ilio-lumbar  artery,  a  branch  of  the 

internal  iliac ;  these  anastomoses  principally  take  place  beneath  the 

iliacus  muscle,  and  if  that  be  divided  and  detached  from  the  ilium, 

they  will  be  brought  into  view. 

The  obturator  artery  nominally  arises  from  the  internal  iliac,  but  in 
a  certain  number  of  cases  it  arises  from  the  external  iliac  by  an  inde- 
pendent origin,  or  by  a  trunk  common  to  it  and  the  epigastric  ;  it 
then  descends  to  reach  the  upper  and  inner  part  of  the  obturator 
foramen,  and  passes  out  through  an  opening  in  the  obturator  mem- 
brane, to  be  distributed  outside  the  pelvis  :  as  it  perforates  this  mem- 
brane it  is  often  joined  by  a  small  branch  given  off  from  the  internal 
iliac,  which  preserves  the  normal  origin  and  course  of  the  artery. 


It  will  be  desirable  at  this  period  to  turn  the  subject 
over.  If  the  previous  dissections  have  been  accomplished, 
this  can  be  done  without  embarrassing  those  engaged  upon 
the  lower  extremity.  The  parts  connected  with  the  region 
of  the  back  will  be  found  described  in  Part  Second,  Dis- 
section Y. 


DISSECTION  Y. 

ANATOMY   OP    THE    PERINEUM. 

As  the  dissection  of  the  perineum  interferes  with  that  of  other 
parts  of  the  body,  it  should  consequently  be  made  in  common,  the 
dissectors  mutually  agreeing  to  suspend  operations  until  it  is  accom- 
plished. It  can  be  done  advantageously  only  on  the  male  subject; 
the  peculiarities  of  the  female  perineum  will  be  found  at  p.  205. 


202  ANATOMY    OF    THE    ABDOMEN,    ETC. 

The  legs  being  flexed,  the  thighs  are  to  be  bent  upon  the  trunk,  anc 
the  nates  made  to  project  over  the  edge  of  the  table,  preserving  then 
position  by  one  or  two  turns  of  a  cord  carried  round  the  right  knee, 
then  under  the  table  to  the  left  knee,  and  finally  made  fast  by  agaii 
attaching  it  to  the  right  knee.  The  subject  being  thus  placed,"tht 
scrotum  and  testicles  should  be  lifted  on  to  the  pubes,  and  kept  oul 
of  the  way  by  hooks  or  pins ;  the  rectum  is  to  be  distended  wit! 
cotton  wool,  tow,  or  similar  material,  and,  when  well  filled,  the  anus 
should  be  made  to  project  by  pressing  it  downward  from  within  tin 
pelvis.  The  perineum  being  washed  and  shaved,  is  then  ready  for 
dissection.  An  elliptical  incision,  commencing  at  the  root  of  the 
scrotum,  its  long  diameter  corresponding  to  the  median  line,  shoulc 
include  the  anus,  and  extend  to  the  coccyx  posteriorly  ;  the  integu- 
ineiit  is  then  to  be  dissected  toward  the  anus. 

The  PERINEUM  is  an  important  surgical  region,  bounded 
on  each  side  by  the  tuberosities  of  the  ischia,  in  front  by 
the  arch  of  the  pubes,  and  behind  by  the  coccyx ;  in  other 
words,  its  boundaries  are  those  of  the  inferior  strait  of  the 
pelvis. 

Immediately  beneath  the  skin,  where  it  becomes  continu- 
ous with  the  mucous  surface  of  the  anus,  the  fibres  of  the 
sphincter  ani  will  present  themselves,  pale  in  color,  and 
indistinctly  characterized.  Elsewhere,  a  layer  of  fat  and 
cellular  tissue,  constituting  the  superficial  fascia,  covers 
in  the  deeper  parts  of  the  perineum  ;  laterally,  between  the 
anus  and  the  ischia  this  is  considerable  in  amount,  and  fills 
a  large  space,  called  the  ischio-rectal  fossa. 

The  superficial  fascia,  consisting  of  two  layers,  is  con- 
nected laterally  with  the  rami  of  the  ischia  and  the  pubes, 
but  through  the  medium  of  the  scrotum  becomes  continuous 
with  the  corresponding  structure  in  the  groin  (pp.  168  and 
195).  Posteriorly,  it  dips  down  in  front  of  the  rectum  to 
join  the  anterior  layer  of  the  triangular  ligament,  or  deep 
fascia  of  the  perineum.  Hence,  abscesses  of  this  region,  or 
extravasation  of  urine  from  rupture  of  the  urethra,  do  not 
extend  backward  behind  the  rectum,  or  laterally  upon  th 
thighs,  but  forward  toward  and  into  the  scrotum,  and  even 
to  the  anterior  part  of  the  abdomen.  In  and  beneath  this 
fascia  will  be  found  a  number  of  vessels  and  nerves. 

The  external  hemorrhoidal  artery  traverses  the  ischio- 
rectal  fossa ;  it  is  an  offset  from  the  internal  pudic  artery, 
a  branch  of  the  internal  iliac,  which  lies  under  the  ramus 
of  the  ischium,  and  is  distributed  to  the  sphincter  and 
levator  ani  muscles  and  to  the  lower  part  of  the  rectum. 
Farther  in  front,  the  internal  pudic  artery  gives  off  the 


il 

i 

: 


S 


ANATOMY    OF    THE    PERINEUM.  203 

superficial  perineal  artery  ;  this  passes  forward  to  the 
scrotum,  giving  off  in  its  course  a  branch  called  the  trans- 
versalis  perinei,  which  crosses  the  perineum  upon  the 
trans  versus  perinei  muscle. 

These  arteries  are  accompanied  by  small  branches  from 
the  internal  pudic  and  perineal  cutaneous  nerves. 

The  internal  pudic  nerve  is  an  offset  from  the  sacral 
lexus,  which  takes  the  course  of  the  internal  pudic  artery, 
nd  divides  into  a  superior  and  inferior  branch,  the  former 
oing  to  the  penis,  the  latter  to  the  scrotum  and  perineum. 

The  perineal   cutaneous   nerve  comes   from   the  lesser 

iatic,  and  ascends  along  the  ramus  of  the  ischium  to 
apply  the  scrotum  and  the  integument  below  the  penis. 

The  preceding  dissection  will  have  exposed  several  mus- 
cles, small  in  size,  but,  with  a  single  exception,  sufficiently 
well  marked  to  be  readily  recognized. 

The  SPHINCTER  ANI  is  an  elliptical-shaped  muscle,  sur- 
ounding  the  anus.  It  arises  from  the  tip  of  the  coccyx, 

d  is  inserted  an  inch  or  more  in  front  of  the  anus  in 
common  with  two  other  muscles,  hereafter  to  be  described, 
into  a  fibrous  spot  called  the  perineal  centre.  Deeper  in 
the  pelvis,  but  continuous  with  this  muscle,  will  be  seen 
the  circular  fibres  proper  to  the  rectum  itself;  these  con- 
stitute the  sphincter  ani  internus  ;  by  removing  all  the  fat 
and  cellular  tissue  from  the  ischio-rectal  fossa,  it  will  be 
seen  that  these  muscles  blend  with,  and  become  lost  in  the 
lower  part  of  the  levator  ani  muscle,  which  comes  down 
from  each  side  of  the  pelvis,  and  surrounds  the  gut,  as 
will  hereafter  be  observed  on  making  a  section  of  the  pelvic 
cavity. 

The  TRANSVERSUS  PERINEI  MUSCLE  is  a  small  bundle  of 
fibres,  occasionally  wanting  on  one  or  both  sides,  which 
arises  from  the  tuberosity  of  the  ischium,  and  is  inserted 
into  the  perineal  centre.  A  slip,  arising  in  common  with 
this,  sometimes  passes  forward,  and  becomes  blended  with 
the  accelerator  urinae ;  this  is  called  the  transversus  perinei 
alter. 

The  ERECTOR  PENIS  arises  from  the  tuberosity  and  ramus 
of  the  ischium  by  a  strong  tendon,  and  forming  a  round, 
fleshy  belly,  is  inserted  on  the  side  of  the  penis  into  the 
strong  fascia  investing  the  corpus  cavernosum. 

The  ACCELERATORES  TIRING  lie  upon  the  corpus  spon- 
giosum  of  the  penis;  arising  from  the  perineal  centre  and 
the  raphe  that  separates  them,  their  fibres  diverge  to 


204  ANATOMY    OF    THE    ABDOMEN,    ETC. 

encircle  the  penis ;  the  posterior  fibres  are  inserted  into  the 
ramus  of  the  pubes  and  ischium,  the  middle  surround  the 
corpus  spongiosum,  and  the  anterior,  spreading  upon  the 
corpora  cavernosa,  are  inserted  into  their  investing  fascia. 

By  dividing   the  muscles  inserted  into  the   perineal   centre,  an< 
reflecting  them,  the  bulb  of   the    corpus    spongiosum  penis  will  b 
exposed,  and,  directly  behind  it,  a  strong  fascia  named  the  triangular 
ligament,  through  which  the    membranous   portion   of  the  urethra 


The  TRIANGULAR  LIGAMENT,  so  called  from  its  occupying 
the  triangular  space  formed  by  the  arch  of  the  pubes,  is 
the  deep  perineal  fascia,  extending  from  one  ramus  of  the 
ischium  and  os  pubis  to  the  other ;  it  is  composed  of  two 
layers,  the  anterior  of  which  unites  with  the  superficial 
fascia  in  front  of  the  anus,  and  the  posterior,  passing 
backward,  invests  the  membranous  urethra  and  prostate, 
and  becomes  continuous  with  the  pelvic  fascia.  It  furnishes 
one  of  the  chief  supports  and  means  of  resistance  to  the 
superincumbent  weight  of  viscera  pressing  down  upon  the 
perineum.  The  anterior  layer  of  the  triangular  ligament 
is  traversed  by  the  urethra,  and  the  edges  of  the  opening 
through  which  it  passes  are  continuous  with  the  fibrous 
sheath  of  the  corpus  spongiosum.  Between  the  two  la}Ters 
lie  the  compressor  muscle  of  the  urethra,  Cowper's  glands, 
and,  for  a  part  of  their  course,  the  external  pudic  arteries, 
and  arteries  of  the  bulb. 

The  artery  of  the  bulb  is  a  branch  of  considerable  size, 
arising  from  the  internal  pudic;  it  passes  transversely  in- 
ward to  the  bulbous  portion  of  the  corpus  spongiosum,  to 
which  it  is  distributed. 

COWPER'S  GLANDS,  one  on  each  side,  are  small  bodies, 
the  size  of  a  pea,  situated  behind  the  bulb  of  the  corpus 
spongiosum,  between  the  two  layers  of  the  triangular  liga- 
ment ;  they  secrete  a  fluid  carried  by  a  duct  into  the  bulb- 
ous portion  of  the  urethra.  Their  size,  and  the  nature  of 
the  locality  in  which  they  exist,  often  render  them  difficult 
to  demonstrate. 

The  erector  penis  muscle  is  to  be  dissected  away  on  one  side,  from 
the  ramus  of  the  pubes  and  ischium,  keeping  close  to  the  bone  ;  this 
will  permit  the  dissection  of  the  internal  pudic  artery. 

The  removal  of  the  erector  penis  shows  the  strong  ten- 
dinous nature  of  that  muscle  at  its  origin  from  the  bone ; 


A' NATO  MY     OF     THE     PERINEUM.  205 

the  other  extremity  being  connected  with  the  corpus  caver- 
nosum,  it  forms  one  of  the  chief  supports  of  the  penis,  and 
is  called  the  cms  penis. 

The  INTERNAL  PUDIC  ARTERY  may  now  be  sought  for, 
and  will  be  found  lying  under  the  edge  of  the  ramus  of  the 
ischium.     This  artery  is  one  of  the  terminal  branches  of  the 
iternal  iliac;  it  passes  out  at  the  greater  sacro-ischiatic 
>ramen,  crosses  the  spine  of  the  ischium,  and  enters  the 
ilvis  again  by  the  lesser  sacro-ischiatic  foramen  to  reach 
ramus  of  the  ischium,  about  an  inch  in  front  of  the 
iberosity  ;  it  passes  along  beneath  the  edge  of  this  to  the 
-mphysis  pubes,  where,  under  the  name  of  the  dorsalis 
mis,  it  runs  the  length  of  the  organ  from  which  it  takes 
name,  to  terminate  in  the  glans  penis. 

The  removal  of  a  calculus  from  the  male  urinary  bladder  is  accom- 

ished  by  an  operation  performed  in  the  perineum,  called  lithotomy, 
bladder  is  reached  by  an  incision  extending  from  the  median  line, 
n  inch  or  more  in  front  of  the  anus,  backward  and  outward,  to  a 
point  midway  between  the  anus  and  the  tuber  ischii.  A  part  of  the 
accelerator  urinse  near  the  bulb  of  the  corpus  spongiosum,  the  trans- 
versus  perinei  muscle,  and  the  transverse  and  superficial  perineal 

teries,  besides  the  skin,  superficial  fascia,  and  triangular  ligament, 
necessarily  divided,  in  order  to  reach  the  membranous  urethra. 

e  knife  of  the  surgeon  is  directed  by  a  sound  introduced  per 
urethram,  and  by  the  guidance  of  this  the  membranous  urethra 
and  prostate  are  incised,  so  that  an  opening  for  the  extraction  of  the 
stone  is  effected.  The  artery  of  the  bulb  may  be  wounded  in  this 
operation,  but  the  internal  pudic  artery  can  never  be  touched  unless 
the  incision  is  carried  too  near  the  ramus  of  the  ischium. 

The  muscles  of  the  female  perineum  differ  little,  except  in 
name,  from  those  of  the  male. 

The  constrictor  vaginae  surrounds  the  orifice  of  the 
vagina,  arising  from  the  perineal  centre,  and  is  inserted  into 
the  corpus  cavernosum  of  the  clitoris  ;  it  corresponds  to 
the  accelerator  urinse. 

The  transversus  perinei  is  inserted  into  the  side  of  the 
constrictor  vaginae. 

The  erector  clitoridis  arises  from  the  ramus  of  the  ischium, 
and  is  inserted  into  the  side  of  the  corpus  cavernosum  of 
the  clitoris. 

The  artery  of  the  bulb  is  distributed  to  the  vagina. 


18 


Tin 


206  ANATOMY     OF     THE    ABDOMEN,    ETC. 

DISSECTION  VI. 

INTERIOR    OF    THE  PELVIS. 

To  examine  the  interior  of  the  pelvis  it  is  necessary  to  detach  one 
of  the  inferior  extremities  with  the  corresponding  os  innorninatum. 
To  do  this,  the  symphysis  pubes  is  to  be  cut  through,  leaving  the 
penis  and  scrotum  attached  to  the  side  to  be  preserved  ;  the  saci 
iliac  articulation  being  found,  and  its  anterior  ligaments  divided, 
making  the  edge  of  the  table  a  fulcrum  and  forcibly  separatin 
the  divided  pubes,  the  dislocation  of  the  ilium  from  the  sacrum 
will  be  effected  ;  the  common  iliac  and  the  branches  of  the  internal 
iliac  are  to  be  divided,  and  the  pelvic  viscera  separated  from  their 
lateral  attachments  on  one  side  only  ;  then  cutting  through  the  sacro- 
ischiatic  ligaments  and  the  gluteus  maximus  muscle  and  skin  ex- 
ternally, the  limb  will  be  separated  and  one-half  of  the  pelvis  re- 
main undisturbed.  The  disadvantage  of  this  method  is  that  one  side 
is  necessarily  sacrificed.  The  sacrum  may  be  sawed  through  upon 
the  median  line  instead  of  dislocating  the  ilium  ;  the  glutei  muscles 
are  then  left  uninjured  upon  both  sides,  but  the  pelvis  is  not  in  so 
favorable  a  condition  for  advantageous  dissection. 

The  position  of  the  pelvic  viscera,  and  the  folds  of  peri- 
toneum which  invest  them  ma}7  now  be  studied. 

It  will  be  seen  that  the  rectum  is  covered  with  perito- 
neum, and  held  in  its  place  along  the  middle  of  the  sacrum 
\)y  a  mesentery  called  the  meso-rectum ;  from  the  rectum  the 
peritoneum  passes  over  the  bladder,  leaving  a  fold  between 
called  the  recto-vesical  fold,  and  which  sometimes  forms  a 
tight  band  or  cord-like  edge  on  its  posterior  surface.  If 
the  subject  be  a  female  one,  we  shall  have  the  uterus  be- 
tween the  bladder  and  rectum,  and  there  will  then  be  two 
folds,  the  recto-uterine  and  the  vesico-uterine.  The  lateral 
reflections  of  the  peritoneum  form  the  false  ligaments  which 
sustain  the  pelvic  viscera.  It  will  be  noticed  that  the  lower 
part  of  the  rectum  and  a  large  part  of  the  lower  half  of  the 
bladder  have  no  peritoneal  coat,  that  membrane  merely 
covering  them  in,  and  then  being  reflected  to  the  sides  of 
the  pelvis.  The  point  at  which  it  is  reflected  from  the  blad- 
der to  the  anterior  abdominal  parietes  should  be  especially 
examined,  to  notice  the  fact  that  it  is  possible  to  perforate 
the  bladder  above  the  pubes  without  implicating  its  serous 
coat.  In  the  female  subject  the  uterus  is  almost,  if  not 
wholly,  covered  by  the  peritoneum,  and  the  thickness  of 
the  wall  between  the  peritoneal  cavity  and  the  vagina,  at 
its  union  with  the  neck  of  the  uterus,  is  so  trifling  that 


INTERIOR    OF    THE    PELVIS.  207 

the  former  might  easily  be  perforated,  in  operations  upon 
the  vagina  near  the  os  uteri. 

The  bladder  is  held  in  its  place  by  five  false  ligaments  ; 
the  two  postei'ior  being  that   portion  of  the  peritoneum 
forming  the  recto-vesical  fold  of  each  side :  the  two  lateral, 
corresponding  with    the   obliterated   hypogastric    arteries 
and  the  vasa  deferentia  in  their  passage  to  the  base  of  the 
bladder;  and  the  superior  being  a  fold  of  peritoneum  pro- 
jected between  the  umbilicus  and  the  summit  of  the  bladder 
by  the  urachus,  the  remains  of  an  obliterated  foetal  canal, 
lesides  these  the  bladder  has  four  true  ligaments ;   two 
iterior,  formed   by  the  pelvic   fascia  reflected   from  the 
ibes  to  its  neck  and  the  front  of  its  anterior  surface,  and 
ro  lateral*  formed  by  the  recto-vesical  fascia,  or  that  por- 
ion  of  the  pelvic  fascia  covering  the  levator  ani  and  re- 
nted from  it  to  the  sides  of  the  bladder. 
In  the  female  subject,  the  peritoneum  is  reflected  from 
uterus  to  the  sides  of  the  pelvis  in  such  a  manner  as  to 
>rm  a  septum  between  it  and  the  bladder,  which  is  called 

broad  ligament. 
In  the  space  between  the  division  of  the  aorta  into  the 
liac  arteries,  and  spreading  over  the  concave  surface  ot 
sacrum,  is  the  hypogastric  plexus  of  the  sympathetic 
nerve,  destined  to  the  pelvic  viscera ;   it  is  formed  from 
the  aortic  plexus,  and  from  branches  of  the  lumbar  nerves; 
it  has  but  few  ganglia,  and  those  small  ones.     From  this 
plexus  originate  the  hemorrhoidal,  vesical,  prostatic,  vagi- 
nal',   uterine,  and  ovarian  plexuses,  supplying  the  parts 
indicated  by  their  names,  but  they  are  only  demonstrable 
b}r  special  dissections. 

Hnving  verified,  these  different  relations  and  attachments  of  the 
pelvic  viscera,  the  next  step  is  to  trace  the  arteries.  The  bladder 
should  be  inflated,  and  kept  so  by  a  string  tied  round  the  penis  ;  it 
is  then  to  be  drawn  by  hooks  to  the  side  from  which  the  os  inno- 
minatum  has  been  removed.  The  divided  extremity  of  the  ureter  is 
to  be  sought  for,  and  also  the  vas  deferens  ;  having  found  and  isolated 
these,  the  peritoneum  is  to  be  dissected  off  from  the  side  of  the  pelvis, 
and  the  arteries  cleared  from  the  surrounding  cellular  tissue,  tracing 
them  as  they  are  one  by  one  given  off  from  the  internal  iliac  and  its 
divisions. 

The  INTERNAL  ILIAC  ARTERY  is  a  short  trunk  of  large 
size,  arising  from  the  common  iliac;  it  dips  into  the  pelvis, 
keeping  close  to  its  walls,  and  divides  into  an  anterior  and 
a  posterior  trunk.  The  artery  lies  upon  the  internal  iliac 


208  ANATOMY    OF    THE    ABDOMEN,    ETC. 

vein  and  the  lumbo-sacral  nerve ;  the  ureter  crosses  it  and 
separates  it  from  the  peritoneum.  The  length  of  the 
internal  iliac  is  subject  to  great  variation,  and  its  branches 
are  often  irregular  as  to  their  precise  point  of  origin,  some- 
times arising  without  the  separation  of  the  vessel  into  two 
trunks ;  they  may  all  be  determined  by  the  parts  to  which 
they  are  distributed. 

The  anterior  trunk  gives  off  the  following  branches : — 

Superior  Yesical,  Obturator, 

Inferior  Vesical,  Ischiatic, 

Internal  Pudic ; 

and  in  the  female  subject,  these  two  in  addition : — 
Uterine,  Vaginal. 

The  Tiypogastric  artery,  during  foetal  existence,  passes  from  the  in- 
ternal iliac  artery,  over  the  bladder  and  along  the  anterior  parietes  of 
the  abdomen,  beneath  the  peritoneum,  to  the  umbilicus,  and  thence, 
with  its  fellow  and  the  umbilical  vein,  to  the  placenta,  forming  the 
umbilical  cord.  At  the  close  of  intra-uterine  life,  it  becomes  oblit- 
erated to  within  an  inch  and  a  half  of  its  commencement,  leaving  an 
impervious  cord ;  the  portion  remaining  pervious  gives  origin  to  the 
superior  vesical  arteries. 

The  superior  vesical  arteries  are  three  or  four  in  number,  arising  at 
intervals  from  the  stump  of  the  hypogastrie,  and  are  distributed  to 
the  upper  part  of  the  bladder ;  the  most  inferior  of  the  branches  is 
sometimes  called  the  middle  vesical  artery. 

The  inferior  vesical  artery  arises  from  the  internal  iliac,  in  common 
with  a  branch  to  the  rectum  ;  it  is  distributed  to  the  base  of  the 
bladder,  the  vesiculse  serainales  and  prostate.  The  branch  to  the 
rectum  is  called  the  middle  hemorrhoidal ;  it  supplies  the  lower  part 
of  the  rectum,  and  the  vagina  in  the  female,  anastomosing  with  the 
superior  and  external  hetrtorrhoidal  arteries  ;  it  sometimes  arises  from 
the  internal  pudic. 

The  obturator  artery,  already  referred  to  (p.  201),  arises  from  the 
anterior  division  of  the  internal  iliac;  it  passes  foiward,  accom- 
panied by  the  obturator  nerve,  which  lies  above  it,  to  the  upper  part 
of  the  obturator  foramen,  beneath  the  horizontal  branch  of  the  pubes, 
where  it  passes  out  of  the  pelvis  and  divides  into  its  terminal  branches. 
The  obturator  sends  a  small  twig  to  the  iliacus  muscle,  and  another 
to  the  posterior  surface  of  the  pubes. 

The  ischiatic  artery  is  the  largest  branch  of  the  anterior  division  of 
the  internal  iliac  ;  it  passes  downward,  lying  upon  the  sacral  plexus 
of  nerves,  and  leaves  the  pelvis,  jnst  in  front  of  the  sciatic  nerve, 
through  the  greater  sacro-ischiatic  foramen,  to  be  distributed  to  the 
muscles  of  the  gluteal  region  and  the  back  of  the  thigh.  Within  the 
pelvis  it  gives  off  small  branches  to  the  rectum  and  base  of  the 
bladder. 

The  internal  pudic  artery  is  another  branch  of  large  size.  It  passes 
down  in  front  of  the  ischiatic  artery,  and  emerges  from  the  pelvis  at 
the  great  sacro-ischiatic  foramen,  crosses  the  spine  of  the  ischium 


INTERIOR    OF    THE    PELVIS.  209 

and  enters  the  pelvis  again  by  the  lesser  sacro  ischiatio  foramen  to 
reach  the  ramus  of  the  ischium,  beneath  the  edge  of  which  it  passes, 
giving  off  the  periueal  branches  described  at  page  202,  and  terminating 
in  the  dorsalis  penis  artery. 

The  uterine  artery,  arising  from  the  anterior  division  of  the  inter- 
nal iliac,  passes  between  the  layers  of  the  broad  ligament  and  reach- 
ing the  neck  returns  to  the  fund  us  of  the  uterus,  giving  off  branches 
to  the  surface  and  substance  of  that  vise  us  ;  it  is  usually  more  or 
less  tortuous,  and  anastomoses  freely  with  the  ovarian  artery,  a  branch 
from  the  abdominal  aorta  analogous  to  the  spermatic  artery  of  the 
male  (p.  180).  During  pregnancy  the  uterine  arteries  increase  greatly 
in  size,  and  become  still  more  tortuous.  The  ovarian  artery  passes 
between  the  layers  of  the  broad  ligament,  and,  after  many  tortuous 
convolutions,  penetrates  the  ovary. 

The  raginal  artery  seldom  arises  directly  from  the  inteiual  iliac; 
given  off  frequently  from  the  uterine,  or  from  the  middle  hemorrhoidal, 
it  passes  down  in  the  posterior  wall  of  the  vagina  to  anastomose,  near 
its  termination,  with  the  corresponding  artery  of  the  other  side.  Both 
the  uterine  and  vaginal  arteries  give  small  branches  to  the  bladder 
and  rectum. 

The  posterior  trunk  of  the  internal  iliac  artery  gives  off 
the  following  branches  : — 

Ilio-lumbar,  Lateral  Sacral,  Gluteal. 

The  ilio-lumbar  artery  passes  upward  and  then  outward,  beneath 
the  external  iliac,  to  the  crest  of  the  ilium  ;  it  there  divides  into  two 
branches,  one  of  which  supplies  the  iliacus  internus  by  ramifications 
between  the  muscle  and  the  bone,  forming  numerous  anastomoses 
with  the  circumfl-exa  ilii  from  the  external  iliac  ;  the  other  branch 
passes  upward  to  supply  the  psoas  and  quadratus  lumborum.  This 
artery  is  analogous  to  the  lumbar  arteries  ;  it  varies  considerably  in 
its  precise  point  of  origin. 

The  lateral  sacral  artery  passes  down  upon  the  side  of  the  sacrum 
to  the  coccyx,  inosculating  with  the  sacra  media.  It  sends  branches 
through  the  anterior  sacral  foramina  to  the  terminal  portion  of  the 
spinal  cord,  and  these,  finally  emerging  at  the  posterior  sacral  fora- 
mina, supply  the  posterior  surface  of  the  sacrum. 

The  gluteal  artery  is  a  short,  thick  trunk,  the  apparent  continuation 
of  the  posterior  division  of  the  internal  iliac;  it  p-isses  out  of  the 
pelvis  at  the  greater  sacro-ischiatic  foramen,  above  the  border  of  the 
pyriformis  muscle,  with  the  superior  gluteal  nerve,  and  is  distributed 
to  the  gluteal  muscles,  as  will  be  seen  in  the  description  of » that 
region. 

The  superior  hemorrhoiJal  artery,  a  branch  of  the  infe- 
rior mesenteric,  will  be  found  distributed  to  the  upper  part 
of  the  rectum;  it  lies  between  the  two  layers  of  peritoneum 
constituting  the  meso-rectum,  and  anastomoses  with  the 
middle  and  external  hemorrhoidal  arteries. 

All  of  the  arteries  just  described  are  accompanied  by 
18* 


210  ANATOMY     OF    THE    ABDOMEN,    ETC. 

veins,  which,  with  the  exception  of  the  hemorrhoidal  am 
spermatic  veins,  empty  into  the  internal  iliac  vein.  The 
hemorrhoidal  veins,  more  or  less  connected  with  the  othei 
veins,  especially  those  about  the  neck  of  the  bladder,  empti 
into  the  inferior  mesenteric  vein,  which  terminates  in  the 
vena  portae.  It  will  thus  be  seen  that  constipation,  or  any 
cause  which  obstructs  the  circulation  of  the  vena  portae 
will  also  arrest  the  blood  in  the  hemorrhoidal  veins,  and 
so  give  rise  to  the  condition  known  as  piles  or  hemorrhoids. 
The  spermatic  and  ovarian  veins  terminate,  the  right  in 
the  vena  cava,  the  left  in  the  renal  vein. 

The  nerves  of  the  pelvic  cavity  are  numerous,  important, 
and  many  of  them  of  large  size. 

The  lumbo-sacral  and  obturator  nerves  have  been  already 
described  (p.  200) ;  they  are  again  seen  at  this  stage  of  the 
dissection,  the  former  joining  the  sacral  plexus,  the  latter 
passing  out  at  the  obturator  foramen  with  the  obturator 
artery. 

The  SACRAL  PLEXUS  is  formed  from  the  four  anterior 
sacral  nerves.  The  fifth  sacral  nerve  terminates  in  the 
perineum,  where  it  unites  with  the  sixth,  or  coccygeal 
nerve,  and  is  distributed  to  the  side  of  the  coccj'x  and 
coccygeus  muscle.  The  sacral  plexus  is  a  broad,  flat, 
nervous  band  lying  upon  the  pyriformis  muscle ;  wTithin 
the  pelvis,  it  furnishes  several  visceral  branches  to  the 
pelvic  organs,  which  unite  with  the  branches  of  the  hypo- 
gastric  plexus,  and  also  muscular  branches  to  the  internal 
pelvic  muscles;  it  then  divides  into  the  following  branches, 
destined  to  external  parts,  viz : — 

Gluteal, 
Internal  Pudic, 
Great  Sciatic, 
Lesser  Sciatic. 

These  all  pass  out  through  the  greater  sacro-ischiatic 
foramen,  and  will  be  described  in  connection  with  the  parts 
to  M'hich  they  are  distributed. 

The  pelvic  fascia,  covering  in  the  obturator  internus 
muscle,  may  be  traced  as  a  single  layer  from  the  brim  of 
the  pelvis  as  far  as  a  white,  tendinous  line  stretching  from 
the  symphysis  pubes  to  the  spine  of  the  ischium  ;  at  this 
line  it  divides  into  two  layers,  one  of  which  continues  over 
the  rest  of  the  obturator  muscle,  and  the  other,  under  the 
name  of  the  recto-vesical  fascia,  passes  clown  to  be  attached 


INTERIOR    OF    THE    PELVIS.  211 

to  the  side  of  the  bladder  and  rectum.    Between  these  two 
la}'ers  is  the  levator  ani  muscle. 

The  LEVATOR  ANI  MUSCLE,  a  broad,  thin  plane  of  mus- 
cular fibres,  forming,  with  its  fellow,  the  floor  of  the  pelvis, 
is  compared  by  Bell  to  a  pair  of  hands  which  dip  down  to 
hold  up  and  support  the  viscera,  the  simile  being  suggested 
by  the  funnel-shaped  manner  in  which  they  embrace  the 
pelvic  contents.     The  muscle  arises  from  the  inner  surface 
of  the  os  pubis,  from  the  tendinous  line  constituting  the 
>int  of  separation  between  the  obturator  and  recto-vesical 
iscia,  and  from  the  spine  of  the  ischium ;  it  is  inserted 
ito  the  lower  part  of  the  rectum,  where  its  fibres  become 
mnected    and    continuous   with   those   of    the    internal 
)hincter,  and  into  the  base  of  the  bladder  and  the  pros- 
ite.     In  the  female,  the  levator  ani  is  inserted  into  the 
ide  of  the  vagina  as  well  as  the  rectum. 

The   two  following   muscles  are  very  difficult   of  demonstration, 
hey  are  to  be  sought  for  between  the  two  layers  of  the  triangular 
igament,  where  they  lie  connected  with  the  membranous  urethra  and 
ibic  bones. 

The  COMPRESSOR  URETHRA,  or  GUTHRIE'S  MUSCLE,  con- 
sists of  two  transverse  layers  of  muscular  fibres,  attached 

y  a  narrow  origin  on  each  side  to  the  ramus  of  the  pubes; 

icy  expand  at  their  central  portion,  one  above  and  the 
>ther  below  the  urethra,  and  are  inserted  into  a  fibrous 

iphe  on  the  median  line,  extending  the  whole  length  of  the 

lembranous  urethra. 

WILSON'S  MUSCLE  is  considered,  when  present,  as  a  part 
>f  the  preceding,  and  as  being  merely  another  attachment 
)f  its  fibres.  It  arises,  tendinous,  from  the  under  part  of 
the  symphysis  of  the  pubes,  and  descends,  fan-shaped,  to 
be  inserted  into  the  upper  layer  of  the  compressor  urethne 
on  the  median  line. 

The  pelvic  viscera  should  now  be  removed,  and  in  such  a  way  as 
to  leave  the  internal  muscles  and  nerves  of  the  pelvis  uninjured  ;  the 
arterial  connections  must  be  divided,  and  the  rectum  dissected  up 
from  the  concavity  of  the  sacrum.  The  penis  should  be  removed 
with  the  viscera,  detaching  it  from  the  arch  of  the  pubes,  by  carrying 
the  knife  close  to  the  bone.  In  the  female,  the  vulva  and  anus  should 
be  included  in  an  elliptical  incision,  and  carefully  dissected  away 
from  the  raini  of  the  ischia  and  pubes.  These  parts  should  be  laid 
aside  for  further  examination. 

Within  the  pelvis  will  be  noticed  the  bellies  and  origins 


ANATOMY     OF    THE    ABDOMEN,    ETC. 


of  two  muscles  which  have  their  insertions  outside ;  thes< 
are  the  obturator  interims  and  the  pyriformis. 

The  OBTURATOR  INTERNUS  MUSCLE  arises  from  the  bon< 
around  the  obturator  foramen,  and  from  the  membran< 
which  stretches  across  it ;  it  forms  a  triangular  belly, 
covered  b}^  the  pelvic  fascia,  which,  tapering  to  a  point, 
passes  out  of  the  lesser  sacro-ischiatic  foramen,  to  be  in- 
serted into  the  digital  fossa  of  the  trochanter  major. 

The  PYRIFORMIS  MUSCLE  arises  from  the  sacrum,  between 
the  first  and  fourth  anterior  sacral  foramina,  from  the 
greater  sacro-ischiatic  ligament,  and  from  a  portion  of  the 
ilium,  forming  a  triangular  belly  which  terminates  in  a 
rounded  tendon,  and  passing  out  at  the  sacro-ischiatic 
foramen,  is  inserted  into  the  digital  fossa  of  the  trochanter 
major. 

The  COCCYGEUS  MUSCLE  is  a  small  collection  of  muscular 
and  tendinous  fibres,  arising  from  the  spine  of  the  ischium, 
and  from  the  lesser  sacro-ischiatic  ligament,  and  inserted 
into  the  side  of  the  coccyx ;  its  lower  border  is  connected 
with  the  levator  ani.  It  is  apt  to  be  mutilated  in  the  re- 
moval of  the  rectum  and  anus. 


DISSECTION  VII. 

1  THE    RECTUM. 

The  pelvic  viscera  may  now  be  examined,  commencing  with  the 
rectum  ;  this  should  be  cleared  from  all  extraneous  tissue,  but  with- 
out separating  it  from  its  connections  with  the  bladder. 

The  RECTUM  is  about  eight  inches  in  length ;  it  follows 
a  curved  direction,  corresponding  to  that  of  the  sacrum, 
and  gradually  increases  in  size,  especially  in  old  people, 
from  its  commencement  to  within  an  inch  and  a  halfLof  the 
anus.  The  last  inch  and  a  half  is  contracted,  and  follows 
a  direction  downward  and  backward  to  its  termination  in 
the  anus.  Its  anterior  surface  is  in  contact  with  the 
bladder  and  its  appendages  in  the  male,  and  the  uterus 
and  vagina  in  the  female,  the  upper  portion  being  separated 
only  by  the  recto-vesical,  or  recto-uterine  fold  of  the  peri- 
toneum, while  the  lower  portion  is  in  direct  apposition  with 
the  bladder,  or  separated  from  it  only  by  cellular  tissue. 
The  rectum,  laid  open  along  its  posterior  aspect,  dis- 


THE    BLADDER.  213 

plays  a  thick  mucous  membrane  lying  chiefly  in  longitudinal 
folds ;  at  the  lower  part,  these  are  called  the  columns  of 
Morgagni,  and  are  generally  three  in  number.  The  mus- 
cular fibres  are  longitudinal  and  circular ;  the  longitudinal 
cease  at  the  lower  part,  and  give  place  to  the  circular  fibres 
which  form  the  internal  sphincter. 

THE    BLADDER. 

The  rectum  must  now  be  removed.  The  ureter  and  vas  deferens 
are  to  be  followed  to  their  terminations.  The  peritoneum  should  be 
dissected  from  off  the  bladder.  *• 

* 

The  BLADDER,  when  distended,  is  of  an  ovoid  shape,  the 
summit  or  superior  end  being  the  smaller ;  it  is  connected 
<ith  the  penis  by  a  somewhat  funnel-shaped  portion,  called 
neck.    In  the  male,  the  neck  is  surrounded  by  the  pros- 
tate ;  in  the  female,  the  place  of  this  is  supplied  by  cellular 
ind  muscular  tissue.     The  summit  of  the  bladder  termi- 
lates  in  the  urachus,  the  remains  of  a  canal,  called  the 
llantois,  which,  during  the  early  part  of  foetal  life,  con- 
iccted  the  bladder  and  the  umbilical  aperture. 

In  addition  to  the  serous,  the  bladder  has  a  muscular 
tnd  a  mucous  coat,  united  together  by  cellular  tissue.  The 
ibres  of  the  muscular  coat  are  arranged  both  in  a  circular 
id  a  longitudinal  manner;  the  circular  fibres  are  chiefly 
found  round  the  neck,  and  constitute  what  is  called  the 
sphincter  vesicse ;  the  longitudinal  are  well  marked,  both 
in  front  and  behind,  and,  from  their  office,  are  named,  col- 
lectively, the  detrusor  urinse. 

The  mucous  coat  of  the  bladder  is  thrown  into  folds,  or 
becomes  smooth,  according  to  the  degree  of  its  distension. 
At  the  lower  and  anterior  part  of  its  interior  is  the  orifice 
of  the  urethra,  the  aperture  of  which  is  partly  closed  by  a 
small  mucous  projection,  called  the  uvula  vesicse.  By 
blowing  through  the  ureters,  their  orifices  will  be  demon- 
strated, as  well  as  the  obliquity  with  which  they  penetrate 
the  bladder.  The  triangle  formed  lay  these  two  orifices, 
and  the  orifice  of  the  bladder,  is  called  the  trigonum  vesicx, 
and  is  made  apparent  by  the  greater  adhesion  of  the  mucous 
membrane  to  the  parts  beneath  than  elsewhere.  Especially 
in  a  hypertrophied  condition  of  the  muscular  coat  of  the 
bladder,  two  muscular  bands,  proceeding  from  the  orifices 
of  the  ureters,  may  be  seen,  on  lifting  the  mucous  coat, 
converging  towards  the  urethral  orifice ;  closely  united 


214 


ANATOMY    OF    THE    ABDOMEN,    ETC. 


with  the  sub-mucous  cellular  tissue,  they  cross  each  othei 
at  their  point  of  convergence,  and  form  the  uvula  vesicae 
they  then  become  continuous  with  the  longitudinal  mus 
cular  fibres  of  the  urethra.  They  are  called  the  muscles  oj 
the  ureters,  and  serve  to  occlude  the  orifice  of  the  uretei 
and  to  open  the  neck  of  the  bladder. 

MALE    ORGANS   OF   GENERATION.1 

VESICUL^E  SKMINALES  AND  PROSTATE. 

The  vesiculae  seminales  lie  imbedded  in  a  mass  of  cellular  tissue 
at  the  base  of  the^ladder;  this  is  to  be  removed,  and  the  prostate  is 
also  to  be  isolated  from  the  veins  and  fascia  investing  it. 

The  VEsrcuL^E  SEMINALES  are  two  flattened,  oblong 
bodies,  situated  upon  each  side  of  the  inferior  and  external 
surface  of  the  bladder,  closely  adhering  to  it,  and  con- 
verging from  a  point  near  the  termination  of  the  ureters 
to  meet  at  the  base  of  the  prostate.  Each  vesicle  consists 
of  a  coiled  and  sacculated  tube,  the  convolutions  of  which 
are  closely  united  to  each  other. 

The  VAS  DEFERENS,  a  firm,  fibrous  tube,  lined  inter- 
nally with  mucous  membrane,  commences  at  the  epididymia 
of  the  testicle,  and  accompanies  the  veins  and  arteries 
composing  the  spermatic  cord,  to  the  internal  abdominal 
ring ;  it  then  leaves  the  vein  and  artery  to  pass  down  into 
the  pelvis,  and,  getting  behind  the  .  bladder,  descends 
between  it  and  the  rectum  to  the  inner  side  of  the  vesi- 
cula  seminalis ;  it  here  becomes  dilated,  assumes  a  some- 
what sacculated  condition,  and  ends  by  blending  with  the 
excretory  duct  of  the  vesicula,  to  form  the  ductus  coin- 
munis  ejaculatorius,  which,  passing  through  the  under  sur- 
face of  the  prostate,  ferminates  in  the  urethra. 

The  PROSTATE  is  a  body  shaped  like  a  chestnut,  which 
surrounds  the  neck  of  the  bladder  and  the  commencement 
of  the  urethra ;  its  pointed  extremity  is  directed  forward. 
It  is  invested  by  a  dense  fascia,  and  by  a  very  noticeable 
plexus  of  veins  called  the  prostatic  plexus,  which  communi- 
cates with  the  dorsal  vein  of  the  penis,  and  the  hemor- 
rhoidal  veins  of  the  rectum. 

The  prostate  is  composed  of  two  lateral  lobes,  the  division 
of  which  is  not  always  well  marked.  The  third  lobe,  d< 

1  The  female  organs  of  generation  are  described  at  the  close  of  this 
dissection. 


THE    PENIS.  215 

scribed  by  Sir  Everard  Home,  being  the  result  of  enlarge- 
ment by  disease  of  that  portion  of  the  organ  situated 
below  the  urethra  and  behind  the  duets  of  the  vesicular 
seminales,  and  which  the  absence  of  resistance  permits  to 
grow  out  in  that  direction  more  freely  than  elsewhere,  is, 
with  great  propriet3^,  described  by  Thompson  as  the  pos- 
terior median  portion.  The  normal  dimensions  of  the 
prostate  are  an  inch  and  a  half  transversely,  an  inch 
longitudinally,  and  three-quarters  of  an  inch  vertically. 

41  The   prostate    consists    of    organic    muscular  fibres, 
arranged    in    a   circular    manner    around   its   long   axis, 
"irough   which    passes    the    urethra.      It   has    no   claim, 
lerefore,  to  be  regarded  as  a  gland  at  all,  in  the  sense  in 
rhich  that  term  is  used  to  classify  certain  structures  in 
human  body,  but  rather  as  a  muscular  body  permeated 
urethral  glands."1    On  section,  the  prostate  is  very  firm 
the  feel,  and  is  of  a  reddish  color.     The  orifices  of  its 
lands  are  numerous,  and  open  into  the  prostatic  part  of 
le  urethra. 

THE  PENIS. 

The  PENIS,  as  has  been  already  seen,  is  connected  to  the 
?lvic  bones  by  the  ligamentum  suspensorium  and  the  two 
•ura  formed  by  the  erectores  penis.  It  is  composed  of  the 
corpora  cavernosa,  corpus  spongiosum,  and  glans.  These 
are  covered  with  integument,  loosely  attached  by  cellular 
tissue,  that  portion  of  it  which  invests  the  glans  being 
called  the  prepuce. 

The  corpora  cavernosa  constitute  the  bulk  of  the  penis ; 
separating  posteriorly,  to  join  with  the  crura,  the^y  unite  at 
the  root  of  the  penis,  and  are  firmly  connected  together  by 
a  fibrous  septum  ;  they  terminate  anteriorly  in  a  blunt  ex- 
tremity, covered  in  by,  and  closely  united  with,  the  glans. 
Flattened  upon  their  superior  surface,  a  slight  groove  re- 
ceives the  dorsal  arter}T  and  vein  and  the  dorsal  nerve  of 
the  penis ;  these  all  extend  to  the  glans.  The  under  surface 
of  the  corpora  cavernosa  is  more  deeply  grooved  to  receive 
the  corpus  spongiosum;  this  commences  at  the  root  of  the 
penis,  in  a  dilated  extremity  called  the  bulb,  which  is  em- 
braced by  the  acceleratores  urina?,  and,  continuing  along  the 
under  surface  of  the  corpora  cavernosa,  expands  at  their 

1  Thompson  011  the  Prostate. 


21G  ANATOMY    OF    THE    ABDOMEN,    ETC. 

termination,  to  form  the  glans  penis.     The  urethra  occi 
pies  the  centre  of  the  corpus  spongiosum. 

The  glans,  being  larger  than  the  surrounding  body 
the  penis,  forms  a  projecting  u  shoulder,"  called  the  coroi 
glandis,  which  is  filled  with  sebaceous  glands,  called  tl 
glands  of  Tyson.  It  is  covered  by  a  delicate  mucous  mei 
brane,  reflected  upon  the  inner  surface  of  the  prepuce,  an< 
continuous  with  the  external  skin  of  the  organ.  The  e: 
ternal  orifice,  or  meatus  of  the  urethra,  opens  in  the  glai 
by  a  vertical  fissure,  and,  from  the  lower  end  of  this,  tin 
mucous  membrane  forms  a  fold  between  the  prepuce  am 
the  gland,  called  thefrenum. 

The  corpus  spongiosum  and  the  corpora  cavernosa  ai 
invested  by  a  dense  elastic  fascia,  called  the  sheath  of  tli 
penis.  The  internal  structure  of  both  these  bodies  and 
the  glans  is  essentially  the  same,  being  composed  of  whs 
is  called  erectile  tissue.  From  the  inside  of  their  investing 
sheaths,  fibrous  bands,  called  trabeculae,  passing  in  different 
directions,  divide  the  whole  interior  into  a  multitude  of 
minute  spaces,  which,  upon  section,  have  a  spongy  aspect, 
and  are  more  or  less  filled  with  venous  blood.  Within 
these  spaces  is  an  intricate  plexus  of  veins,  completely 
filling  them,  and  with  which  the  arteries,  ramifying  in  the 
trabeculse,  communicate.  The  blood  is  received  from  the 
branches  of  the  internal  pudic  artery,  and  returned  by  the 
vena  dorsalis,  which,  joined  by  short  branches  entering  it 
upon  the  upper  surface  and  at  the  root  of  the  penis,  empties 
into  the  prostatic  plexus. 

The  urethra  extends  from  the  orifice  of  the  bladder  to 
the  meatus  of  the  glans,  and  is  divisible  into  three  portions: 
prostatic,  membranous,  and  spongy.  It  should  be  exposed 
by  laying  it  open  with  the  scissors  along  the  superior 
surface. 

The  prostatic  urethra  is  surrounded  by  the  prostate,  the 
portion  of  which  lying  above  the  urethra  is  much  thinner 
than  that  below.  Upon  its  inferior  wall  is  a  small  project- 
ing crest,  called  the  veru  montanum,  or  coput  galinaginis ; 
the  depression  on  each  side  of  this  is  called  the  prostatic 
sinus,  the  floor  of  which  is  perforated  by  the  orifices  of  the 
prostatic  ducts ;  these  may  be  demonstrated  by  squeezing 
the  prostate;  this  will  force  out  the  secretion  through 
their  apertures.  At  the  anterior  part  of  the  veru  montanum 
is  an  opening,  called  the  sinus  pocularis,  and  upon  the  sides 
of  this  the  ejaculatory,  or  seminal  ducts,  have  their  opening ; 


THETESTES.  217 

their  orifices  may  likewise  be  demonstrated  by  compress- 
ing the  vesiculae  seminales. 

The  membranous  urethra  is  that  portion  between  the 
prostate  and  the  bulb;  it  passes  through  the  triangular 
ligament,  and  is  less  than  an  inch  in  length.  It  is  sur- 
rounded by  areolar  tissue  and  veins,  and  by  the  compressor 
urethra?,  or  Guthrie's  muscle. 

The  spongy  portion  of  the  urethra,  surrounded  by  the 
erectile  tissue  of  the  corpus  spongiosum,  extends  from  the 
bulb  to  the  meatus.  In  the  bulb,  the  urethra  forms  a  dila- 
tation, and  at  this  point  may  be  found  the  two  orifices  of 
the  ducts  of  Cowper's  glands ;  a  second  dilatation  occurs 
about  an  inch  from  the  meatus,  and  is  called  the  fossa 
namcularis.  The  mucous  membrane  of  the  urethra  is  thin 
and  delicate,  and  is  sometimes  thrown  into  longitudinal 
folds;  it  has  numerous  follicular  orifices,  one  of  which,  in 
the  fossa  navicularis,  is  of  large  size,  and  is  called  the 
lacuna  magna. 

THE  TESTES. 

The  testes  are  contained  in  an  envelope  called  the  scro- 
tum. They  may,  however,  remain  in  the  abdomen,  or  be 
arrested  in  the  inguinal  canal,  instead  of  descending  from 
the  lumbar  region  to  the  scrotum,  as  the}^  should  at  the 
close  of  intra-uterine  life.  In  such  cases,  they  are  usually 
imperfect  or  small,  "contrary  to  an  old  authority,"  says 
John  Bell;  "it  having  been  said,  Hhat  the  testicles  are 
seated  externally  for  chastity's  sake;  for  such  live  wights 
as  have  their  stones  hid  within  their  body  are  very  lecher- 
ous, do  often  couple,  and  get  many  young  ones.' " 

The  SCROTUM  is  composed  of  a  tegumentary  covering, 
and  a  fascia  continuous  with  the  superficial  fascia  of  the 
abdomen  and  perineum;  it  is  divided  into  two  compart- 
ments by  a  septum,  the  position  of  which  is  indicated  ex- 
ternally by  a  raphe  continued  along  the  under  side  of  the 
penis  and  into  the  perineum.  Beneath  the  integument  is  a 
reddish  tissue,  called  the  dartos,  composed  of  non-striated 
muscular  fibres,  and  in  which  resides  the  contractile  power 
belonging  to  the  scrotum.  The  testicle  lies  within  a  serous 
membrane,  derived  from  the  peritoneum  of  the  abdomen, 
which  was  pushed  before  it  in  its  descent  during  foetal  life; 
the  connection  between  the  portion  of  membrane  envelop- 
ing the  testicle  and  the  peritoneum  of  the  general  cavity 
19 


218  ANATOMY     OF    THE     ABDOMEN,    ETC. 

of  the  abdomen  being  obliterated,  it  forms  a  separate  shul 
sac,  called  the  tunica  vaginalis. 

In  the  adult,  as  well  as  in  infants,  there  is  constant!; 
found,  near  the  point  where  the  testicle  and  epididy mil- 
become  continuous,  a  small  cellule-fibrous  and  fatty  body 
the   size  of  a   pea,  covered   with   serous  membrane,  an< 
evidently  analogous   to   the   appendices   of  other   serous 
membranes,  especially  of  the  peritoneum  ;  it  is  sometime* 
pediculated,  and  at  others  consists  merely  of  a  little  mem- 
branous fold.     This  is  called  the  appendix  of  the  testicle. 

The  testicle  should  be  examined  by  following  ont  the  vas  deferens 
till  it  is  lost  in  the  epididymis,  and  then  by  tracing  that  body  to  its  con- 
nection with  the  main  part  of  the  gland,  removing  with  the  scissors 
all  the  cellular  tissue  which  surrounds  it.  The  close  adherence  of 
the  parts  to  each  other  makes  the  dissection  a  slow  one. 

The  TESTES  are  oval  glands,  suspended  in  the  scrotum 
by  the  spermatic  cord ;  the  left  is  usually  larger  and 
placed  lower  than  the  right.  Along  its  posterior  side, 
close  to  that  part  at  which  the  tunica  vaginalis  is  reflected 
to  the  testicle,  is  a  long  narrow  body,  called  the  epididy- 
mis. The  lower  part  of  this  is  continuous  with  the  vas 
deferens,  which  turns  and  is  reflected  upward  beside  the 
epididymis,  being  tortuous  at  first,  but  subsequently  be- 
coming straight  as  it  unites  with  the  other  elements  of  the 
spermatic  cord. 

The  dissection  will  show  that  besides  the  serous  coat, 
the  testicle  has  also  a  fibrous  coat  of  a  pearly  aspect,  called 
the  tunica  albuginea ;  this  not  only  preserves  the  shape  of 
the  gland  but  sends  processes  into  its  interior  for  its  further 
support ;  one  of  these,  larger  than  the  rest,  lies  along  the 
posterior  aspect  of  the  gland,  and  is  called  the  mediastinum 
test  is. 

The  substance  of  the  testicle  is  a  pulpy  mass,  made  u] 
of  lobules  composed  of  the  convoluted  tubuli  seminiferi, 
which,  if  seized  by  the  forceps,  may  be  drawn  out  in  long 
threads.  The  lobules  all  converge  towards  the  mediasti- 
num, where  their  tubuli  unite  and,  becoming  larger,  con- 
tinue to  the  upper  end  of  the  testis,  and  finally  terminate 
in  the  vas  deferens.  Sometimes  there  is  an  offset  from  the 
vas  deferens  or  from  the  lower  part  of  the  epididymis,  con- 
sisting of  a  prolongation  of  the  tubuli,  extending  up  the 
cord  and  terminating  in  a  blind  extremity ;  it  is  called  the 
vasculum  aberrans  of -Holler. 


FEMALE    ORGANS    OF    GENERATION.  210 

The  vas  deferens  occupies  the  posterior  part  of  the  sper- 
matic cord,  and  is  easily  distinguishable  by  its  cord-like 
feel.  Its  course  has  been  already  described  (p.  214). 

The  spermatic  cord,  besides  the  vas  deferens,  is  made  up 
of  the  spermatic  artery  and  veins,  and  numerous  lymphatics, 
which  terminate  in  the  lumbar  glands.    The  spermatic  veins 
ire   extremely  subject   to    enlargement,   constituting   the 
mdition  known  as  varicocele,  and  always  make  up  a  very 
msiderable  portion  of  the  cord ;  they  may  be  seen  com- 
jncing  at  the  lower  part  of  the  testicle  in  numerous  small, 
•rtuous  branches,  which  surround  the  vas  deferens,  and  are 
tiled  the  rete  pampiniforme ;  these,  gradually  enlarging, 
lally  terminate  in  the  single  trunk  of  the  spermatic  vein, 
or  near,  the  external  abdominal  ring.     The  cord  also 
mtains  the  spermatic  plexus  of  nerves,  which,  coming 
mi  the  aortic  and  renal  plexuses,  accompanies  the  sper- 
latic  artery.  The  genital  branch  of  the  genito-crural  nerve 
id  the  scrotal  branch  of  the  musculo-cutaneous  nerve  (p. 
),  are  elements  of  the  cord;  and  the  cremaster  muscle 
.  165),  variably  developed,  the  spermatic  fascia  and  the 
>ro-cellular  remains  of  the  tube  of  peritoneum,  once  com- 
Limicating  with  the  abdominal  cavity,  also  make  up  a  large 
>rtkm  of  its  bulk. 


FEMALE    ORGANS   OF   GENERATION. 

The  relations  of  the.  organs  peculiar  to  the  female  sex 
have  been  already  studied;  it  remains  to  examine,  in  de- 
tail, the  uterus  and  its  appendages,  including  the  external 
organs,  or  vulva.  The  latter  will  be  examined  first. 

The  prominence  of  the  pubes,  covered  with  a  develop- 
ment of  hair,  is  called  the  mons  Veneris.  Extending  down- 
ward from  this  are  the  labia  majora,  composed  of  two  folds 
of  integument,  meeting  above  and  below,  filled  with  fat  and 
cellular  tissue,  and  lined  internally  with  mucous  membrane; 
the  round  ligament  of  the  uterus  terminates  in  these1.  Infe- 
riorly,  upon  separation,  a  transverse  fold  will  be  seen 
stretching  across  between  them,  called  the  fourchette ;  in 
women  who  have  borne  children,  this  is  usually  destroyed. 
Superiorly  will  be  noticed  the  clitoris,  a  small  projecting 
body,  analogous  to  the  penis  of  the  male,  composed  of  two 
corpora  cavernosa,  attached  on  each  side  to  the  ramus  of 
the  ischium,  and  receiving  the  insertions  of  the  erector 
clitoridis  muscle.  The  clitoris  is  composed,  like  the  penis, 


220  ANATOMY    OF    THE    ABDOMEN,    ETC. 

of  erectile  tissue,  and  is  surmounted  by  a  glans  surrounded 
by  a  prepuce.  From  this  prepuce,  a  longitudinal  fold  of 
mucous  membrane  descends  on  each  side,  and  becomes 
blended  with  the  labia  majora ;  these  folds  are  called  the 
nymphae,  or  labia  minor  a.  Between  these,  and  just  above 
the  aperture  of  the  vagina,  is  the  orifice  of  the  urethra, 
surrounded  by  an  elevated  margin.  The  urethra  is  about 
an  inch  and  a  half  in  length,  and  lies  in  the  upper  wall 
of  the  vagina,  from  which  it  cannot  be  separated ;  it  is 
very  elastic,  and  capable  of  great  distension.  The  orifice 
of  the  vagina  is  transversely  elliptical ;  in  the  virgin  it  is 
sometimes  partly  closed  by  a  circular  fold  of  mucous  mem- 
brane, called  the  hymen ;  this  is  destroyed  by  sexual  inter- 
course, or  by  child-birth,  but  its  former  presence  is  indicated 
by  small  elevated  excrescences,  called  carunculae  myrti- 
formes.  Just  anterior  to  the  hymen  may  be  found  the 
orifices  of  two  ducts,  one  on  each  side,  often  made  apparent 
from  being  distended  with  sebaceous  matter;  by  laying 
these  open,  each  may  be  traced  to  a  round  body,  the  size 
of  a  large  pea,  called  the  gland  of  Bartholinus. 

The  parts  just  described  are  supplied  by  branches  of  the 
internal  puclic  artery,  and  by  offsets  from  the  lumbar  and 
sacral  plexuses  of  nerves. 

The  bladder  may  now  be  dissected  from  the  uterus,  and  the  vagina 
laid  open  with  the  scissors  along  its  superior  surface. 

The  vagina  occupies  a  position  corresponding  to  the  axis 
of  the  outlet  of  the  pelvis,  and  reaches  from  the  cervix  of 
the  uterus,  which  projects  into  it,  to  the  external  opening 
of  the  vulva ;  it  is  placed  between  the  bladder  and  the 
rectum,  and  at  its  sides  is  embraced  by  the  levatores  ani 
muscles.  Its  orifice  is  surrounded  by  a  sphincter  muscle 
(p.  203),  and  its  upper  extremity  is  dilated ;  its  internal 
surface  is  lined  with  mucous  membrane,  thrown  into  rugae, 
more  marked  near  the  entrance  than  higher  up ;  these  meet 
in  a  raphe  which  extends  along  the  centre  of  both  the  ante- 
rior and  posterior  walls ;  the  two  raphes  being  called  the 
columns  of  the  vagina.  Beneath  the  mucous  membrane  is 
a  layer  of  contractile  tissue  similar  to  the  dartos,  and 
external  to  this  a  layer  of  cellular  tissue ;  the  upper  part  of 
the  posterior  wall  of  the  vagina  is  covered  by  the  perito- 
neum of  the  recto-uterine  fold. 

The  UTERUS,  with  the  exception  of  its  mouth  and  neck, 
is  covered  with  peritoneum,  which  spreads  out  on  both 


FEMALE    ORGANS    OF    GENERATION.  221 

sides  into  what  is  called  the  broad  ligament,  stretching 
across  the  pelvis,  as  already  seen,  and  forming  a  sort  of 
septum  between  the  bladder  and  rectum.  It  is  pyriform 
in  shape,  convex  posteriorly  and  flattened  anteriorly,  and 
divided  into  a  fundus,  body,  cervix,  and  os. 

The  uterus  may  be  laid  open  with  the  scissors,  introduced  at  the 
5,  making  a  longitudinal  incision  to  be  afterward  crossed  by  a  trans- 
verse one  at  the  fundus. 

The  substance  of  the  uterus  is  composed  of  muscular 
fibres.     In  its  natural  state,  the  muscular  portion  is  seen 
as  a  firm,  compact,  fibrous  tissue ;  in  the  impregnated  con- 
lition,  this  becomes  hypertrophied  and  vastly  more  appa- 
?nt.    The  orifices  of  divided  veins  will  be  seen  on  the  face 
f  the  section  ;  these,  in  the  pregnant  uterus,  are  called  the 
inuses. 

The  cavity  of  the  uterus  is  lined  with  mucous  membrane 
mtinuous  with  that  of  the  vagina ;  it  is  triangular  in 
tape,  and  about  the  size  of  an  almond  j  the  base  of  the 
•iangle  corresponds  to  the  fundus  of  the  organ,  the  fundus 
>ing  the  broad  portion  surmounting  the  body,  or  central 
>art.  The  cavity  is  constricted  at  the  union  of  the  body 
rith  the  cervix,  the  cervix  being  the  portion  between  this 
mstriction  and  the  mouth,  or  os  uteri.  The  point  of  con- 
viction between  the  cervix  and  body  is  sometimes  called 
os  uteri  internum.  The  canal  of  the  cervix  is  slightly 
lilated,  and  the  oblique  folds  of  the  mucous  membrane,  in 
lis  part,  have  received  the  name  of  arbor  vitae  uteri.  The 
uteri,  before  parturition,  consists  simply  of  a  rounded 
•ifice  with  thick  lips  ;  after  childbirth  it  becomes  a  trans- 
verse fissure,  the  posterior  lip  of  which  is  the  longest. 

The  uterus  is  supplied  with  blood  from  the  uterine  and 
ovarian  arteries.  The  uterine  veins  are  large  and  numerous, 
and  form  plexuses  upon  each  side  of  the  organ  ;  its  nerves 
are  derived  from  the  hypogastric  and  ovarian  plexuses,  and 
from  branches  of  the  third  and  fourth  sacral  nerves. 

The  appendages  of  the  uterus  are  the  broad  ligaments, 
the  round  ligaments,  the  Fallopian  tubes,  and  the  ovaries. 
The  broad  ligaments,  consisting  simply  of  the  two  peri- 
toneal layers  covering  the  anterior  and  posterior  uterine 
surfaces,  and  then  reflected  upon  the  walls  of  the  pelvis, 
have  been  already  referred  to. 

The  round  ligaments  are  round  cords  of  fibrous  tissue 
attached  to  the  sides  of  the  fundus  uteri,  which,  passing 

19* 


222  ANATOMY    OF    THE    ABDOMEN,    ETC. 

upward  and  outward,  to  the  internal  inguinal  ring  am 
through  the  inguinal  canal,  like  the  spermatic  cord  in  the 
male,  are  lost  in  the  mons  Veneris  and  labia  majora. 

The  Fallopian  tubes,  about  four  inches  in  length,  are  eacl 
connected  by  one  end  with  the  side  of  the  fund  us  of  tin 
uterus ;  the  other  end  is  loose  in  the  cavity  of  the  pelvis 
Their  canals  are  very  minute,  but  traceable  with  a  fin< 
probe  to  the  openings  at  the  angles  of  the  cavity  of  thi 
uterus,  with  the  mucous  membrane  of  which  their  own 
comes  continuous.     The  outer  termination  of  the  tube  it 
free  in  the  peritoneal  cavity;  it  is  dilated  and  surround* 
by  a  circular,  fringe-like  fold,  called  the  corpus  fimbriatum^ 
or  morsus  diaboli.     It  will  be  noticed  that  there  is  thus 
communication  between  the  cavity  of  the  uterus  and  that 
of    the   peritoneum,    forming    a   single   exception    to   the 
general  rule  that  serous  membranes  are  shut  sacs. 

The  OVARIES  are  two  white,  oblong  bodies,  with  either  a 
smooth  or  scarred  surface,  bulging  from  the  posterior  aspect 
of  the  broad  ligaments,  anchwith  which  they  are  connected 
by  their  anterior  margins.  They  are  attached  to  the  uterus 
by  their  inner  extremity,  through  the  medium  of  rounded 
cords  called  the  ligaments  of  the  ovaries.  The  ovary  con- 
sists of  a  fibrous  structure  containing  small  vesicles,  named 
Graafian,  and  the  peritoneum  surrounds  the  whole  organ, 
except  at  its  attached  border.  Their  dimensions  are  very 
variable,  but  may  be  stated,  in  a  general  way,  as  an  inch 
and  a  half,  by  three-quarters  of  an  inch  in  diameter,  and 
half  an  inch  in  thickness. 

The  ovaries  are  supplied  lay  the  ovarian  arteries,  which 
anastomose  with  the  uterine.  The  ovarian  plexus  of  nerves, 
derived  from  the  aortic  plexus,  accompanies  the  ovarian 
artery,  and  the  uterine  nerves  are  also,  in  part,  distributed 
to  them. 

It  is  not  easy  for  the  student  to  tell  which  is  the  front 
and  which  the  back  of  the  uterus;  the  ovaries,  when  present, 
will  tell  him  ;  they  being  alwaj^s  placed  on  the  posterior 
aspect  of  the  broad  ligament ;  in  their  absence,  he  must 
remember  that  the  uterus  is  convex  posteriorly,  and  flat 
anteriorly. 


ANTERIOR    FEMORAL    REGION.  223 

DISSECTION  VIII. 

ANTERIOR    FEMORAL   REGION. 

In  studying  the  anatomy  of  femoral  hernia,  the  superficial  struc- 
tures of  the  anterior  femoral  region  have,  in  part,  been  examined. 
The  incision  of  the  skin  may  now  be  carried  down  the  front  of  the 
thigh  to  the  knee,  and  the  integument  reflected;  several  cutaneous 
nerves  will  be  exposed  by  this  process. 

The  CUTANEOUS  NERVES  are  branches  of  the  external 
cutaneous,    genito-crural    and    crural    nerves,    all    being 
ranches  of  the  lumbar  plexus.     The  external  cutaneous 
rierces   the  deep  fascia  just  below  the  anterior  superior 
>inous   process   of  the  ilium,  and   is  distributed  to  the 
(tegument  of  the  anterior  part  of  the  gluteal  region  and 
outside  of  the  thigh.    The  crural  branch  of  the  genito- 
•ural  nerve  is  small  in  size,  and,  emerging  from  the  sheath 
>f  the  femoral  artery,  is  distributed  to  the  anterior  aspect 
)f  the   thigh.     The  crural   nerve,  appearing  just   below 
"'oupart's  ligament  from  between  the  psoas  and  iliacus 
mscles,  divides  into  two  branches.     One  of  them,  deeper 
than  the  other,  subdivides  to  supply  the  muscles  on  the 
fore  part  of  the  thigh  and  the  pectineus  muscle  on  the 
inside.      The   other   division   is   composed   of    cutaneous 
branches,  distributed   to  the  integument  of  the  anterior 
aspect  of  the  thigh  as  far  down  as  the  patella.    The  largest 
of  these  branches  is  called  the  long  saphena  nerve;  this 
accompanies  the  femoral  artery  on  its  outer  side,  and  at 
the  opening  in  the  tendon  of  the  adductor  magnus  muscle, 
leaving  the  artery  and  passing  beneath  the  sartorius  mus- 
cle, becomes  subcutaneous  and  descends  the  inner  side  of 
the  leg  to  the  inner  border  of  the  foot. 

The  internal  saphena  vein,  especially  if  distended  with 
blood,  will  be  easily  traced,  in  its  superficial  course,  from 
the  inside  of  the  foot,  along  the  inner  border  of  the  leg, 
behind  the  inner  condyle,  upward  to  the  saphenous  open- 
ing. This  vessel  affords  an  excellent  opportunity  to  exa- 
mine the  venous  values ;  they  are  formed  from  the  internal 
lining  membrane,  and  are  usualty  in  pairs,  and  of  a  semi- 
lunar  shape ;  their  situation  is  indicated  externally  b}'  the 
dilatation  of  the  vessel  above  them. 

Upon  the  outside  of  the  thigh  the  deep  fascia,  or  fascia 
lata,  will  be  found  to  become  more  aponeurotic,  and,  at  its 


224       ANATOMY    OF    THE    LOWER    EXTREMITY. 

upper  part,  to  divide  into  two  layers,  between  which  lies 
the  tensor  vaginae  femoris. 

The  TENSOR  VAGINAE  FEMORIS  is  a  short  and  thick  mus- 
cle, arising  from  the  anterior  superior  spinous  process  and 
a  portion  of  the  crest  of  the  ilium  ;  it  is  inserted  into  tin 
fascia  lata  between  its  two  laj-ers,  at  a  point  five  or  si: 
inches  below  that  of  its  origin. 

The  fascia  lata  may  be  removed  as  far  as  the  anterior  border  of  the 
tensor  vaginae  muscle,  but  it  should  not  be  divided  transversely  until 
the  vastua  externus  is  dissected.  The  removal  of  that  part  of  the 
fascia  in  front  of  the  thigh  exposes  the  sartorius  and  rectus  muscles. 
In  dissecting  the  sartorius  it  will  be  found  advantageous  to  remove 
its  anterior  sheath  without  disturbing  the  posterior  adhesions  which 
keep  the  muscle  in  place  :  when  this  is  accomplished  it  may  be  dis- 
sected posteriorly,  but  it  is  so  long  a  muscle  that  it  is  difficult  to  keep 
it  tense,  or  to  dissect  it  neatly. 

The  SARTORIUS  MUSCLE  arises  from  the  anterior  superior 
spinous  process  of  the  ilium,  and  crosses  the  thigh  obliquely 
to  the  inside  of  the  knee,  where  it  forms  a  thin,  flat  tendon 
which  is  inserted  into  the  inner  tuberosity  of  the  tibia  by 
an  aponeurotic  expansion,  which  loses  itself  in  the  fibrous 
tissues  surrounding  the  knee-joint. 

In  dissecting  the  origins  of  the  three  following  muscles,  they  must 
be  free  from  all  tension  ;  but  in  preparing  their  bellies  and  insertions 
they  should  be  made  tense,  and  this  will  be  accomplished  by  bending 
the  knee  upon  the  thigh.  The  length  and  rlaccidity  of  the  sartorius 
permit  its  being  drawn  to  one  side,  so  as  not  to  interfere  with  the  dis- 
section of  the  parts  beneath.  The  second  head  of  the  rectus  is  not 
easily  seen,  as  it  is  very  short;  by  lifting  the  muscle  upward  and 
inward  it  may  be  isolated  from  the  surrounding  parts,  and  brought 
into  view. 

The  RECTUS  FEMORIS  MUSCLE  lies  upon  the  front  of  the 
femur,  forming  a  beautiful  muscular  mass,  the  fibres  of 
which  radiate  from  a  central  longitudinal  line  in  a  bipenni- 
form  manner.  It  arises  b}^  two  tendinous  heads,  one  from 
the  anterior  inferior  spinous  process  of  the  ilium,  just  below 
the  origin  of  the  sartorius  ;  the  other  from  the  upper  surface 
of  the  acetabulum ;  it  is  inserted  by  a  broad  flat  tendon 
into  the  upper  border  of  the  patella. 

The  VASTUS  EXTERNUS  MUSCLE  is  partly  covered  in  by 
the  fascia  lata  into  which  the  tensor  vaginae  femoris  is  in- 
serted ;  it  forms  the  bulk  of  the  outer,  fleshy  part  of  the 
thigh ;  it  arises  from  the  base  of  the  trochanter  major,  and 
from  the  whole  length  of  the  linea  aspera,  and  is  inserted 


E 


ANTERIOR    FEMORAL    REGION.  225 

into   the  outer   side   of  the   patella,  forming   a   common 
aponeurotic  tendon  with  the  rectus  muscle. 

The  YASTUS  INTERNUS  MUSCLE  forms  the  bulk  of  the 
fleshy  portion  of  the  lower  part  of  the  thigh  at  its  inner 
side,  giving  the  limb  its  characteristic  outline ;  it  arises 
from  the  anterior  and  lateral  surfaces  of  the  femur,  and 
the  whole  length  of  the  linea  aspera ;  its  lower  end 
>rminates  in  an  aponeurosis,  which,  blending  with  that  of 
the  rectus,  is  inserted  into  the  inner  border  of  the  patella, 
"he  upper  part  of  the  muscle  is  hidden  beneath  the  rectus 
id  sartorius  muscles;  the  adductor  muscles  are  insepara- 
)ly  connected  with  that  portion  attached  to  the  linea  aspera. 
'he  portion  lying  beneath  the  rectus  muscle,  the  fibres  of 
rhich  run  longitudinally  from  the  inter-trochanteric  line 
the  patella,  is  sometimes  described  as  a  separate  muscle, 
died  the  crurseus.     The  sub-crurasus  muscle  is  a  small 
>undle  of  fibres  beneath  the  cruraeus,  arising  from  the  front 
irt  of  the  femur,  and  inserted  into  the  capsule  of  the 
:nee-joint. 

These  three  muscles  are  sometimes  described  as  one  mus- 
?le  with  three  heads ;  the  patella  is  then  considered  as  a 
isamoid  bone,  and  the  ligamentum  patellae,  inserted  into 
tubercle  of  the  tibia,  as  the  real  tendon  of  insertion  to 
three  muscles,  combined  under  the  name  of  triceps  ex- 
msor  cruris.    If  the  crumeus  is  looked  upon  as  a  separate 
inscle,  the  term  quadriceps  is  used. 

These  muscles  are  all  supplied  by  branches  of  the  crural 
irve,  and  the  femoral  artery  sends  off  irregular  muscular 
twigs,  which  penetrate  them  on  their  under  surface. 

The  muscles  upon  the  inner  and  upper  part  of  the  thigh  almost  in- 
variably become  dried  and  defaced  from  the  delay  occasioned  by  the 
examination  of  other  parts,  after  their  exposure  in  the  dissection  of 

moral  hernia  ;  if  they  have  been  kept  properly  moist,  they  will 
owever  still  be  found  in  tolerable  condition. 

If  the  subject  be  entire,  the  knees  should  be  bent  and  the  soles  of 
the  two  feet  placed  in  contact  with  the  heels  pushed  up  and  so  ap- 
proximated to  the  pelvis  that  they  will  retain  their  position.  If  the 
limb  is  separated  from  the  trunk,  the  ilium  must  be  fixed  by  blocks, 
and  the  muscles  of  the  inside  of  the  thigh  rendered  as  tense  as  cir- 
cumstances will  permit. 

The  muscles  of  the  inner  side  of  the  thigh  are  the  three 
adductors  (longus,  brevis,  and  magnus),  with  the  gracilis 
and  pectineus.  The  gracilis  is  the  longest  and  most  inter- 
nal ;  superficial  to  the  others  are  the  pectineus  and  the 


226       ANATOMY    OF    THE    LOWER    EXTREMITY. 

adductor  longus,  and  beneath  these  the  adductors  brevi; 
and  magnus. 

The  GRACILIS  MUSCLE  arises  by  a  thin,  flat,  and  broi 
tendon  from  the  side  of  the  symphysis  pubes  and  from  th< 
ramus  of  the  pubes  and  ischium  ;  it  forms  a  long,  ribbon-lik( 
belly,  which,  passing  down  on  the  inside  of  the  thigh,  ter- 
minates in  a  tendon,  rounded  at  first,  but  becoming  flat- 
tened, and  is  inserted  into  the  head  of  the  tibia,  beneath 
the  expanded  insertion  of  the  sartorius. 

The  ADDUCTOR  LONGUS  MUSCLE  consists  of  a  large  fleshy 
belly,  arising  by  a  round,  tendinous  origin  from  the  front 
of  the  os  pubis,  and  inserted  into  the  middle  third  of  the 
linea  aspera  by  an  aponeurosis  which  is  partially  confounded 
with  that  of  the  adductor  magnus.  The  dissection  of  this 
muscle  at  its  upper  part  will  expose  the  profunda  artery, 
and  at  its  insertion  the  femoral  artery  will  be  seen  in  close 
relation  to  it. 

Between  this  muscle  and  the  femur  lies  the  PECTTNEUS, 
arising  by  a  broad  and  flat  muscular  origin  from  the 
ilio-pectiueal  line,  and  inserted  into  the  ridge  leading  from 
the  lesser  trochanter  to  the  linea  aspera.  It  is  not  easy 
to  find  the  line  of  separation  between  this  muscle  and  the 
conjoined  tendon  of  the  psoas  and  iliacus,  the  insertion  of 
which  into  the  lesser  trochanter  may  now  be  seen  (p.  200). 

The  TRIANGLE  or  SCARPA  is  the  triangular  depression  in 
the  upper  part  of  the  thigh,  the  base  of  which  is  formed  by 
Poupart's  ligament,  the  outer  side  by  the  inner  border  of 
the  sartorius,  and  the  inner  side  by  the  superior  border  of 
the  adductor  longus.  The  femoral  artery  runs  through  the 
centre  of  this  space,  with  the  femoral  vein  internal  to  it ; 
half  an  inch  external  to  the  artery  is  the  crural  nerve,  at 
first  deep-seated  between  the  psoas  and  iliacus,  afterward 
becoming  more  superficial. 

The  FEMORAL  ARTERY  extends  from  "Poupart's  ligament 
to  the  point  at  which  it  perforates  the  adductor  magnus 
muscle ;  it  is  covered  in  by  a  strong  sheath,  common  to  it 
and  the  vein,  and  occupies  the  depression  existing  between 
the  adductor  muscles  on  the  inside  of  the  thigh  and  those 
which  cover  the  femur  upon  the  outside ;  it  lies  upon  the 
psoas,  pectineus,  and  adductor  longus  muscles,  and  the 
femoral  vein,  except  at  the  upper  part,  where  it  is  upon  its 
inner  side,  lies  almost  directly  behind  it ;  it  is  accompanied 
by  the  long  saphena  nerve.  The  artery  disappears  through 
an  aperture  in  the  tendon  of  the  adductor  magnus  muscle, 


ANTERIOR    FEMORAL    REGION.  227 

at  the  union  of  the  middle  and  lower  third  of  the  thigh, 
and  which  is  the  commencement  of  a  fibrous  canal,  formed 
by  the  tendons  of  the  adductor  magnus  and  vastus  interims 
muscles,  called  Hunter's  canal ;  the  sartorius  muscle,  usu- 
ally called  the  satellite  of  the  femoral  artery,  crosses  the 
thigh  at  such  constantly  varying  angles,  that  its  precise 
relation  to  it  is  by  no  means  constant.  The  artery  may 
sometimes  be  found  split  into  two  trunks  below  the  origin 
of  the  profunda ;  these,  however,  always  unite  before  the 
vessel  perforates  the  adductor  magnus.  The  point  of  elec- 
tion for  applying  a  ligature  to  the  femoral  artery,  is,  the 
thigh  being  rotated  outward,  at  the  apex  of  Scarpa's  trian- 
gle, where  the  sartorius  muscle  crosses  the  vessel ;  it  cor- 
responds to  the  bisection  of  a  line  drawn  from  the  centre 
of  Foupart's  ligament  to  the  posterior  edge  of  the  inner 
mdyle  of  the  femur,  b}^  a  transverse  line  indicating  the 
>per  fourth  of  the  thigh. 

The  superficial  branches  given  off  by  the  femoral  artery 
ive  been  already  dissected  and  described,  at  p.  195,  in 
mnection  with  the  anatomy  of  femoral  hernia. 
At  a  variable  distance,  viz :  from  one  half  to  two  inches 
ilow  Poupart's  ligament,  the  femoral  artery  gives  off',  pos- 
iriorly,  a  large  branch,  nearly  equal  in  size  to  the  main 
trunk  itself,  and  called  the  profunda  artery.  This,  passing 
backward  behind  the  adductor  longus,  breaks  into  branches 
which  perforate  the  adductor  muscles,  and  are  distributed 
to  the  parts  on  the  back  of  the  thigh. 

The  dissection  of  the  profunda  is  with  difficulty  accomplished,  with- 
out destroying  parts  yet  to  be  dissected,  owing  to  the  number  of  its 
branches,  the  confined  limits  of  the  space  they  occupy,  and  the  depth 
to  which  they  penetrate.  The  scissors  will  be  found  useful  at  this 
time,  and,  by  the  aid  of  hooks  and  by  a  judicious  position  of  the  limb, 
the  soft  fat  and  cellular  tissue  surrounding  the  arteries  may  be  re- 
moved, and  the  branches,  if  not  too  much  meddled  with  by  the  for- 
ceps, neatly  displayed. 

The  profunda  gives  off  an  external  and  an  internal  cir- 
cumflex artery,;  one  or  both  of  these  sometimes  arise  directly 
from  the  femoral. 

The  external  circumflex  is  the  larger  of  the  two  ;  it  passes  outward 
beneath  the  rectus  muscle  and  divides  into  three  branches,  or  sets  of 
branches,  viz  :  ascending,  to  inosculate  with  the  gluteal  artery  on  the 
dorsum  of  the  ilium,  near  its  crest ;  middle,  which  curve  around  the 
femur,  just  beneath  the  greater  trochanter,  toinosculate  with  the  gluteal 
and  internal  circumflex  arteries  ;  and  descending,  which  are  distrib- 
uted to  the  muscles  of  the  outside  of  the  thigh. 


228   ANATOMY  OF  THE  LOWER  EXTREMITY. 

The  internal  circumflex  passes  beneath  the  heads  of  the  adductor 
muscles  on  the  inside  of  the  thigh,  and  is  only  to  be  farther  traced 
by  their  division ;  it  supplies  these  muscles,  sends  a  branch  to  th< 
hip-joint,  and  inosculates  with  the  external  circumflex,  obturator,  an 
ischiatic  arteries. 

The  terminal  branches  of  the  profunda  are  called  the  perforating 
arteries,  because  they  pass  through  foramina  in  the  adductor  tendons 
to  reach  the  back  part  of  the  thigh.  They  are  usually  three  in  num- 
ber ;  they  anastomose  freely  with  each  other,  with  the  isehiatic  and 
internal  circumflex  arteries  above,  and  with  the  articular  branches  of 
the  popliteal  artery  iuferiorly.  One  of  these  arteries  supplies  the  nutri- 
ent branch  to  the  femur. 

These  branches  of  the  femoral  artery  are  all  accompanied 
by  veins  which  unite  to  form  the  profunda  vein;  this 
enters  the  femoral  vein  an  inch  or  more  below  Poupart's 
ligament. 

The  continuation  of  the  femoral  artery  furnishes  muscu- 
lar branches  to  the  muscles  contiguous  to  it,  and  as  it  is 
about  to  perforate  the  adductor  maguus  tendon,  gives  off 
a  branch  called  the  anastomotica  magna. 

The  anastomotica  magna  is  not  usually  of  large  size,  nor  always  con- 
stant in  its  point  of  origin,  not  unfrequeutly  arising  from  the  popliteal 
artery  ;  it  is  accompanied  by  the  long  saphena  nerve,  and  descending 
to  the  inner  condyle,  inosculates  with  the  superior  internal  articular 
branch  of  the  popliteal.  In  very  finely  injected  subjects,  numerous 
anastomoses  may  be  traced  between  this  artery  and  other  branches 
distributed  to  the  neighborhood  of  the  knee-joint. 

The  pectineus  and  adductor  longus  muscles  may  now  be  divided  in 
the  middle,  and  their  ends  reflected.  The  arteries  should  be  preserved 
so  far  as  possible. 

In  removing  these  muscles,  the  obturator  nerve  and  its 
branches  should  be  sought  for ;  emerging  from  the  pelvis 
(p.  199)  it  is  distributed  to  the  muscles  of  the  inner  side  of 
the  thigh,  and  a  long  branch  passing  behind  the  pectineus, 
descends  to  the  knee,  where  it  joins  with  branches  of  the 
long  saphena  nerve. 

Small  branches  of  the  obturator  artery  will  also  be  found 
at  the  upper  part  of  these  muscles. 

The  ADDUCTOR  BREVIS  MUSCLE  lies  immediately  beneath 
the  two  muscles  just  divided;  arising  by  a  narrow  origin 
from  the  external  surface  and  ramus  of  the  os  pubis,  and 
passing  very  obliquely  inward,  it  is  inserted  by  a  broad 
tendon,  behind  the  pectineus,  into  the  upper  part  of  the 
linea  aspera. 

The  ADDUCTOR  MAGNUS  MUSCLE,  the  deepest  of  the  three 


GLUTEAL    REGION.  229 

adductors,  forms  the  bulk  of  the  upper  part  of  the  thigh, 
and  separates  the  muscles  of  the  anterior  and  posterior 
femoral  regions;  superiorly  it  lies  beneath  the  adductor 
brevis,  which  should  consequently  be  removed.  It  aris.es 
from  the  rami  of  the  pubes  and  ischium,  and  from  the 
tuberosity  of  the  ischium,  and  is  inserted  into  the  inter- 
trochanteric  line,  and  the  whole  length  of  the  linea  aspera, 
as  far  as  the  inner  condyle,  where  it  terminates  in  a 
rounded  tendon.  At  its  lower  part  it  becomes  confounded 
with  the  adductor  longus  and  the  vastus  interims  muscles, 
its  upper  part  it  is  pierced  by  the  perforating  arteries, 
id  lower  down  it  has  a  large,  oval,  and  tendinous  open- 
ig,  converted  into  a  canal  by  the  tendon  of  the  vastus 
iternus  muscle,  called  Hunter's  canal,  and  through  which 
>s  the  femoral  vessels. 

By  detaching  the  origin  of  the  adductor  magnus,  the  obturator  ex- 
jrnus  muscle  will  be  exposed. 

The  OBTURATOR  EXTERNUS  MUSCLE  arises  from  the  rami 
)f  the  pubes  and  ischium,  and  from  a  part  of  the  surface 
)f  the  obturator  membrane ;  it  forms  a  triangular  belly, 
id  its  fibres  converge  to  a  rounded  tendon,  which  is  in- 
jrted  into  the  digital  fossa  of  the  great  trochanter. 
The  obturator  artery  (p.  208),  after  emerging  from  the 
ilvis,  divides  into  two  branches,  one  of  which  forms  a 
jircle  around  the  membrane  beneath  the  obturator  muscle, 
md  sends  an  articular  twig,  through  the  notch  of  the 
itabulum,  to  the  head  of  the  femur,  which  it  reaches  by 
leans  of  the  round  ligament ;  the  other  branch  supplies 
the  obturator  and  adductor  muscles,  and  unites  with  the 
iternal  circumflex  artery. 


DISSECTION  IX. 

GLUTEAL   REGION. 

The  subject  should  be  turned  over,  and  a  high  block  placed  beneath 
the  thighs,  in  such  a  way  that  the  pelvis  may  hang  over  its  edge,  and 
yet  remain  fixed  firmly  enough  for  dissection  ;  the  thigh  should  be 
rotated  inward,  and  the  foot  should  lie  upon  its  outer  side.  An 
incision  is  to  be  made  obliquely  outward  from  the  upper  part  of  the 
sacrum,  to  a  point  a  hand's  breadth  below  the  greater  trochanter ;  this 
should  penetrate  to  the  muscle,  and  the  flaps  be  reflected  by  dissect- 
20 


230       ANATOMY    OF    THE   tioWER    EXTREMITY 


1 


ing  in  the  direction  of  its  fibres.  The  skin  is  thick  and  tongh,  and 
there  is  a  deep  layer  of  fat  beneath  it,  which  will  probably  be  found 
more  or  less  infiltrated  with  the  fluids  which  have  gradually  gravitatec 
into  the  part  while  dependent. 

The  glutens  maximus,  which  is  the  first  muscle  expose 
is  composed  of  coarse  bundles   of  fibres,  between  whicl 
penetrate  prolongations  from  its  sheath.     It  is  one  of  the 
most  difficult  muscles  in  the  body  to  dissect  neatly,  though 
in  a  favorable  subject,  and  when  well  dissected,  few  present 
a  more  showy  appearance. 

The  GLUTEUS  MAXIMUS  MUSCLE  arises  from  the  posterior 
fifth  of  the  crest  of  the  ilium,  and  of  the  bone  beneath, 
from  the  lateral  tubercles  of  the  sacrum,  the  sacro-iliac 
and  the  greater  sacro-ischiatic  ligaments,  and  from  the 
side  of  the  coccyx  ;  its  upper  half  is  inserted  into  a  thick, 
flat  tendon,  covering  in  the  greater  trochanter  and  con- 
tinuous with  the  fascia  lata  of  the  thigh  ;  the  lower  portion 
is  inserted  into  the  rough  line  on  the  femur,  leading  from 
the  trochanter  major  to  the  linea  aspera.  Beneath  this 
broad  tendon  is  a  large  S3rnovial  bursa.  The  upper  border 
of  this  muscle  is  closely  adherent  to  the  aponeurotic  ex- 
terior of  the  glutens  medius  muscle,  by  means  of  the  fascia 
lata ;  its  lower  border  forms  the  fold  of  the  nates,  and 
overlaps  the  origins  of  the  muscles  of  the  back  of  the  thigh. 

This  muscle  is  to  be  divided  transversely,  and  its  two  ends  are  to 
be  reflected  ;  this  will  expose  the  gluteus  medius. 

In  dividing  the  gluteus  maximus,  a  number  of  arterial 
twigs,  distributed  to  the  muscle,  will  be  cut  across ;  they 
are  muscular  branches  of  the  gluteal  and  ischiatic  arteries; 
a  few  ascending  twigs  from  the  external  circumflex  will 
also  be  seen. 

The  LESSER  SCIATIC  NERVE,  coming  from  the  sacral 
plexus,  emerges  with  the  ischiatic  artery  at  the  sacro-ischi- 
atic foramen.  Its  branches  supply  the  integument  and 
the  gluteus  maximus,  which  it  penetrates  at  its  lower 
border ;  some  of  its  branches  descend  and  are  distributed 
upon  the  posterior  aspect  of  the  thigh  ;  one  of  these,  larger 
than  the  others,  is  called  the  middle  posterior  cutaneous 
nerve. 

The  GLUTEUS  MEDIUS  MUSCLE,  partially  covered  by  the 
gluteus  maximus,  and  elsewhere  by  a  dense  aponeurosis, 
which  cannot  be  dissected  from  the  muscular  tissue  beneath, 
arises  from  the  anterior  four  fifths  of  the  crest  of  the  ilium, 


: 


GLUTEAL    REGION.  231 

and  from  the  superior  curved  line  of  the  external  surface 
of  that  bone,  being  closely  connected  at  its  anterior  border 
with  the  gluteus  minimus  and  the  tensor  vaginse  femoris ; 
its  fibres  converge  to  be  inserted  by  a  thick  tendon  into 
the  external  surface  of  the  trochanter  major.  The  gluteal 
artery  emerges  at  its  posterior  border,  and  a  large  branch 

mines   upon  this  muscle,  between   it   and   the  gluteus 

aximus. 


This  muscle  may  now  be  removed,  by  dividing  it  an  inch  above 
insertion,  and  reflecting  its  muscular  belly.     A  confused  mass  of 
areolar  tissue,  arteries,  nerves,  and  muscles,  remains,  which  is  to  be 
tiently  cleared  up,  by  gradually  removing  the  areolar  tissue  with 
e  scissors  and  forceps,  following  out  the  arteries  and  nerves  ;  the 
ing  of  them  should  be  commenced  at  the  point  at  which  they 
lerge  from  the  pelvis. 

The  gluteal  artery  emerges  between  the  glutens  medius 

id  pyriformis  muscles,  and  is,  as  has  been  stated  (p.  209), 

branch  of  the  internal  iliac,  the  terminal  one  of  its  pos- 
>rior  division ;  it  breaks  up  into  branches  as  soon  as  it 

icrges  from  the  pelvis.  The  superficial  branch  goes  to 
gluteus  maxim  us ;  the  deep  superior  passes  upward 
md  forward  to  the  anterior  superior  spinous  process  of  the 
lium,  between  the  gluteus  medius  and  minimus  muscles, 
md  inosculates  with  the  circumflexa  ilii  and  external  cir- 
cumflex arteries ;  the  deep  inferior  branch  ramifies  upon  the 
gluteus  minimus,  in  the  neighborhood  of  the  trochanter 

id  capsule  of  the  hip-joint. 

The  gluteal  nerve,  corning  from  the  sacral  plexus,  emerges 
rith  the  gluteal  artery,  and  divides  into  two  branches  ;  one, 

jsing  upward  toward  the  crest  of  the  ilium,  and  supply- 
ing the  gluteus  medius  and  minimus ;  the  other,  passing 
forward,  sends  branches  to  these  muscles,  and  terminates 
in  the  tensor  vaginae  femoris. 

The  iscliiatic  artery,  one  of  the  terminal  branches  of  the 
anterior  division  of  the  internal  iliac,  emerges  below  the 
pyriformis  muscle,  and  passes  downward  between  the 
trochanter  and  the  tuberosity  of  the  ischinm,  supplying 
muscular  branches  to  the  gluteus  maximus  and  posterior 
muscles  of  the  thigh ;  it  also  sends  a  branch  to  the  great 
sciatic  nerve,  named  comes  nervi  ischiatici,  which  accom- 
panies it  to  the  popliteal  space. 

The  GREAT  SCIATIC  NERVE  is  the  continuation  of  the 
sacral  plexus.  It  emerges  below  the  pyriformis  muscle  as 
a  broad,  flat  cord,  three-fourths  of  an  inch  in  width;  it 


232       ANATOMY    OF    THE    LOWER    EXTREMITY. 

descends  between  the  trochanter  and  tnberosity  of  the 
ischium,  and  will  be  further  seen  in  the  dissection  of  the 
posterior  region  of  the  thigh.  It  supplies  the  heads  of  the 
posterior  muscles  of  the  thigh,  and  gives  off  some  small 
branches  which  ramify  on  the  capsule  of  the  hip-joint. 
Not  unfrequently  it  is  split  into  two  trunks,  one  of  which 
passes  through  the  pyrifbrmifi ;  sometimes  the  whole  nerve 
perforates  that  muscle. 

The  internal  pudic  artery  emerges  below  the  pyriformis 
muscle,  in  front  of  the  ischiatic  artery,  at  the  great  sacro- 
ischiatic  foramen,  passes  under  the  greater  sacro-ischiatic 
ligament,  and  ascends  along  the  ramus  of  the  ischium ;  it 
is  accompanied  by  the  internal  pudic  nerve ;  its  branches 
and  distribution  have  already  been  described  (p.  205). 

In  dissecting  these  arteries,  the  following  muscles  will 
have  been  exposed. 

The  GLUTEUS  MINIMUS  MUSCLE  arises,  fan-shaped,  from 
the  surface  of  the  ilium,  between  the  acetabulum  and  the 
middle  curved  line  of  that  bone,  and  is  inserted  into  the 
summit  and  inside  of  the  great  trochanter;  anteriorly  this 
muscle  is  blended  with  the  glutens  medius. 

The  PYRIFORMIS  MUSCLE,  arising  from  the  sacrum,  has 
already  been  described  as  seen  within  the  pelvis  (p.  212)  ; 
the  part  external  to  the  pelvis  will  now  be  found  narrowing 
to  its  inseftion  and  separated  from  the  gluteus  minimus  by 
the  gluteal  artery.  It  arises  from  the  concave  surface  of 
the  sacrum,  between  the  first  and  fourth  anterior  sacral 
foramina,  from  the  greater  sacro-ischiatic  ligament,  and 
from  a  portion  of  the  ilium ;  forming  a  thick,  flattened 
belly,  it  passes  out  at  the  great  sacro-ischiatic  notch,  tapers 
to  a  rounded  tendon,  blending  with  that  of  the  gluteus 
minimus,  and  is  inserted  into  the  digital  fossa  of  the  great 
trochanter. 

Some  little  difficulty  is  often  experienced  by  the  student  in  deter- 
mining the  three  next  muscles.  A  bundle  of  muscular  fibres  presents 
itself  just  below  the  pyriformis,  and  crossed  by  the  great  sciatic  nerve ; 
it  is  composed  of  the  tendon  of  the  internal  obturator  muscle  sur- 
rounded by  its  two  dependent  muscles,  the  gemelli ;  if  this  bundle 
of  fibres  be  carefully  separated  longitudinally,  the  glistening  tendon 
of  the  obturator  will  be  exposed,  and  the  two  gemelli  may  be  distinctly 
defined,  on  one  side  and  the  other,  though  they  cannot  be  isolated 
from  the  obturator  tendon. 

The  OBTURATOR  INTERNUS  MUSCLE  has  been  partly  seen 
in  another  dissection  (p.  212) ;  it  arises  within  the  pelvis 


POSTERIOR    FEMORAL    REGION.  233 

from  the  margin  of  the  bone  which  surrounds  the  obturator 
foramen,  and  from  the  membrane  which  stretches  across  it; 
it  passes  over  the  lesser  sacro-ischiatic  notch,  which  acts  as 
a  pulley  on  which  its  tendon  plays  in  the  change  of  direction 
which  it  assumes  to  reach  its  insertion.  The  belly  of  the 
muscle  is  broad  and  flat,  and,  tapering  to  a  rounded  tendon, 
embraced  by  the  gemelli  muscles,  is  inserted  into  the  digital 
>ssa  of  the  great  trochanter.  On  dividing  this  muscle,  it 
ll  be  seen  that  the  ischiatic  notch  is  covered  with  cartilage 
id  provided  with  a  synovial  bursa. 

The  GEMELLUS  SUPERIOR  arises  from  the  spine  of  the 
3hium  ;  the  GEMELLUS  INFERIOR  from  the  upper  and  pos- 
irior  part  of  the  tuberosity  of  the  ischium.  The  superior  is 
isually  the  smaller  of  the  two,  and  they  embrace,  and  either 
'holly  or  partially  conceal,  the  tendon  of  the  obturator 
luscle,  into  which  some  of  their  fibres  are  inserted,  while 
rest  are  inserted  with  that  tendon  into  the  digital  fossa 
the  greater  trochanter.  These  two  muscles  thus  con- 
fute appendages  of  the  obturator  interims,  and  form,  as 
were,  a  "marsupium,"  or  pouch,  to  that  muscle,  which, 
>m  having  connected  with  it  a  well-marked  bursa,  was 
)metimes  called,  by  the  old  anatomists,  the  "bursalis,"  or 
marsupialis"  muscle.  The  gemellus  superior  is  sometimes 
>sent. 

The  QUADRATUS  FEMORIS  MUSCLE  lies  next  below  the 
gemellus  inferior;  it  is  a  flat  and  quadrangular  muscle, 
arising  from  the  external  border  of  the  tuberosity  of  the 
ischium,  and  inserted  into  the  linea  quadrati  at  the  pos- 
terior and  lower  part  of  the  greater  trochanter.  This 
muscle  is  tendinous  at  its  insertion,  and  its  lower  border 
is  in  relation  with  the  adductor  magnus ;  it  is  crossed  by 
the  great  sciatic  nerve,  and  the  internal  circumflex  artery 
emerges  at  its  upper  border.  Just  above  this  muscle  will 
be  seen  the  tendon  and  part  of  the  belly  of  the  obturator 
externus  muscle,  going  to  be  inserted  into  the  digital  fossa. 


DISSECTION  X. 

POSTERIOR   FEMORAL   REGION. 

An  incision  is  to  be  carried  down  the  back  of  tbe  tbigb,  a  short 
distance  below  the  fold  of  the  knee-joint,  and  the  integument  reflected. 

20* 


234        ANATOMY    OF    THE    LOWER    EXTREMITY. 

Upon  the  fascia  lata,  thus  exposed,  will  be  found  a  numbei 
of  cutaneous  nerves,  on  the  inside,  derived  from  the  obtu- 
rator nerve,  on  the  outside  from  the  external  cutaneous 
nerve  (p.  199),  and  in  the  middle  from  the  middle  posterioi 
cutaneous  branch  of  the  lesser  sciatic  nerve  (p.  230).  A1 
the  lower  part  of  the  thigh,  the  external  saphena  vein, 
ascending  from  the  foot  along  the  median  line  of  the  cali 
of  the  leg,  may  be  seen  penetrating  the  popliteal  space 
join  the  popliteal  vein. 

The  fascia  lata  is  to  be  removed  and  the  muscles  are  to  be  dissected. 
The  sciatic  nerve  and  its  divisions  are  to  be  particularly  respected. 

The  posterior  femoral  muscles  will  be  found  supplied 
with  arteries  from  the  circumflex  and  perforating  branches 
of  the  profunda  artery. 

The  BICEPS  MUSCLE  is  the  most  external  of  this  region, 
and,  in  common  with  the  two  muscles  to  be  next  described, 
is  covered  in  at  its  upper  part  by  the  glutens  maximus.  It 
arises  from  the  tuberosity  of  the  ischium  by  a  tendon,  only 
artificially  separable  from  the  other  muscles  arising  at  that 
point,  and  also  from  the  femur  by  a  second  head  attached 
to  the  linea  aspera ;  these  two  heads  unite  to  be  inserted 
lay  a  round  tendon  into  the  head  of  the  fibula  and  outer 
tuberosity  of  the  tibia.  This  tendon  forms  the  outer  ham- 
string.1 

The  SEMI-TENDINOSUS  MUSCLE  lies  upon  the  inner  side  of 
the  posterior  femoral  region.  At  its  origin  from  the  tuber- 
osity of  the  ischium,  and  for  some  distance  below  it,  it  is 
not  easily  separable  from  the  biceps;  it  forms  a  compara- 
tively short  and  stout  belly,  terminating  in  a  long  tendon, 
which  is  inserted  into  the  inner  surface  of  the  tibia  below 
the  tendon  of  the  gracilis,  both  of  these  tendons  being 
covered  in  by  the  expanded  insertion  of  the  sartorius. 

The  SEMI-MEMBRANOSUS  MUSCLE  lies  beneath  the  two  pre- 
ceding muscles,  and  derives  its  name  from  the  membrani- 
form  tendon  which  characterizes  its  origin.  It  arises  from 
the  tuberosity  of  the  ischium,  in  common  with  the  biceps 
and  semi-tendinosus  muscles,  and  is  inserted  by  a  tendon 
which  has  three  different  points  of  attachment,  viz :  an 
internal,  to  the  inner  tuberosity  of  the 'tibia;  a  middle 

1  The  student  can  assist  his  memory  to  retain  the  fact  that  the 
biceps  forms  the  outer  hamstring,  by  the  first  two  letters  in  the  word 
Boston.  (13.  0.  biceps,  outer.) 


POPLITEAL    SPACE.  285 

which  is  continuous  with  the  fascia  covering  the  popli- 
teus  muscle,  and  a  posterior,  which  expands  upon  the 
posterior  surface  of  the  knee-joint  and  is  attached  to  the 
outer  condyle  of  the  femur,  constituting  what  is  called  the 
ligament um  posticurii  Winslowii  of  the  knee-joint.  The 
tendons  of  the  semi-membranosus  and  semi-tendinosus  form 
the  inner  ham-string,  and  with  that  of  the  gracilis,  from  a 
fancied  resemblance,  derived  from  their  divergence,  have 
received  the  name  of  the  pes  anserinus. 

The  SCIATIC  NERVE,  surrounded  b}' a  consider  able  amount 
of  fat  and  areolar  tissue,  will  have  been  traced  in  the  fore- 
going dissection  (p.  231).     At  the  upper  part  of  the  thigh 
it   is    comparatively   superficial,   there    being   no   muscle 
between  it  and  the  integument ;  it  then  passes  underneath 
the  long  head  of  the  biceps,  and  down  upon  the  outer  side 
of  the  median  line  of  the  thigh  to  the  popliteal  space,  giving 
>ff,  in  its  course,  branches  to  the  muscles  of  the  posterior 
amoral  region,  between  which  it  lies,  and  a  single  articular 
>ranch  to  the  knee-joint.     Toward  the  lower  part  of  the 
tigh,  it  divides  into  the  popliteal  and  peroneal  branches ; 
)metimes  this  division  takes  place  higher  up,  even  before 
emerging  from  the  pelvis;  in  which  case,  as  has  been  seen, 
me  of  the  branches  perforates  the  pyriformis  muscle. 

POPLITEAL    SPACE. 

The  POPLITEAL  SPACE  is  the  diamond-shaped  interval 
itween  the  biceps  and  semi-tendinosus  and  semi-membran- 
>sus  muscles  above,  and  the  separated  heads  of  the  gas- 
trocnemius  muscle  below;  its  base,  or  floor,  being  the  flat 
surface  of  the  femur  above  the  condyles ;  the  fascia  lata 
and  integument  cover  it  superficially,  and  it  is  traversed  by 
the  popliteal  artery  and  vein,  and  the  popliteal  nerve  with 
its  branches.  The  relative  position  of  these  is  as  follows  : 
The  popliteal  nerve  is  the  most  superficial,  and  its  situation 
corresponds  to  the  long  diameter  of  the  popliteal  space ; 
immediately  beneath  the  nerve  is  the  popliteal  vein,  and 
directly  under  the  vein,  the  popliteal  artery,  the  nerve,  vein, 
and  artery  lying  superimposed  one  upon  another.  Be- 
tween the  nerve  and  the  vein  there  is  usually  an  interval 
filled  with  fat. 

The  branches  of  the  sciatic  nerve  which  are  superficial 
are  to  be  examined  first. 

Theperonea/  division  of  the  sciatic  nerve  is  smaller  in  size  than  the 
popliteal  ;  it  accompanies  the  tendon  of  the  biceps  mnscle  to  the  head 


236   ANATOMY  OF  THE  LOWER  EXTREMITY. 

of  the  fibula,  where  it  curves  around  that  bone,  passing  between  il 
and  the  peroneus  longus  muscle,  dividing,  as  it  disappears,  into  th< 
anterior  tibial  and  musculo-cutaneous  nerves.  The  peroueal  nerv< 
before  disappearing,  besides  giving  off  a  few  small  cutaneous,  mus- 
cular, and  articular  branches,  furnishes  an  important  snperficii 
branch,  the  comiimnicans  peronei ;  this  passes  down  upon  the  outer 
side  of  the  call  of  the  leg  to  about  its  middle,  where  it  is  joined  by  a 
branch  from  the  popliteal,  called  the  conimunicans  poplitei,  and  the 
two,  uniting,  constitute  the  external,  or  short  sapheua  nerve.  This 
union  does  not  always,  however,  take  place,  one  of  the  nerves  losing 
itself  in  the  integument,  and  the  other,  continuing  downward,  pursues 
the  course  and  takes  the  name  of  the  short  saphena  nerve. 

The  popliteal  nerve  lies  superficial  to  the  popliteal  vein,  and,  at  the 
lower  border  of  the  popliteal  space,  becomes  the  posterior  tibial  nerve  ; 
while  in  the  space,  it  gives  off  muscular  branches  to  the  heads  of  the 
gastrocnemius  muscle,  an  articular  branch  to  the  interior  of  the  knee- 
joint,  and  a  superficial  branch,  called  the  cominunicans  poplitei ;  this  is 
larger  than'the  communicans  peronei,  with  which,  after  passing  be- 
tween the  two  heads  of  the  gastrocnemius,  it  unites,  half-way  down 
the  leg  ;  their  union  constitutes-  the  external,  or  short  saphena  nerve. 
This  nerve  descends  the  leg  on  the  outer  side  of  the  tendo  Achillis, 
curves  round  the  outer  malleolus,  and  is  distributed  to  the  outside  of 
the  foot  and  little  toe. 

The  POPLITEAL  YEIN  lies  upon  the  popliteal  artery,  and 
receives  the  external  saphena  vein,  which,  after  a  superficial 
course  up  the  back  of  the  leg,  here  penetrates  to  terminate 
in  the  popliteal  vein. 

The  POPLITEAL  ARTERY  lies  deeply  imbedded  in  the 
popliteal  space;  it  is  the  continuation  of  the  femoral 
artery;  commencing  at  the  point  where  that  vessel 
emerges,  after  passing  through  the  opening  in  the  tendon 
of  the  adductor  magnus  muscle,  it  terminates  at  the  lower 
border  of  the  popliteus  muscle,  by  dividing  into  the  ante- 
rior and  posterior  tibial  arteries ;  this  division  sometimes 
takes  place  at  a  point  higher  up. 

The  popliteal  artery  gives  off  four  articular  branches, 
viz  :  superior  and  inferior  external  articular,  and  superior 
and  inferior  internal  articular.  These  wind  around  the 
knee-joint  to  its  front,  supplying  the  lower  part  of  the 
femur,  the  heads  of  the  tibia  and  fibula,  and  the  joint 
itself;  they  anastomose  very  freely  with  each  other,  with 
the  anastomotica  magna,  and  the  recurrent  branch  of  the 
anterior  tibial  artery.  The  inferior  articular  arteries  pass 
beneath  the  lateral  ligaments  of  the  knee-joint,  and  the 
superior  articular  beneath  the  tendon  of  the  biceps  on  the 
outside,  and  that  of  the  adductor  magnus  muscle  on  the 
inside.  Two  large  muscular  branches,  called  the  sural,  pass 


FRONT  OP  LEG  AND  DORSUM  OP  FOOT.   237 

downward,  to  supply  the  heads  of  the  gastrocnemius  mus- 
cle, and  the  azygos  articular,  a  small  branch,  almost  always 
broken  or  destroyed  in  removing  the  fat  from  the  popliteal 
space,  springing  from  the  posterior  aspect  of  the  artery, 
penetrates  the  ligamentnm  posticum  Winslowii,  to  supply 
the  internal  structures  of  the  knee-joint. 


DISSECTION  XL 

FRONT   OF   THE    LEG   AND    DORSUM   OF    THE    FOOT. 

The  dissection  now  reverts  to  the  front  of  the  limb,  and  is  continued 
by  making  an  incision  from  the  knee  downward  and  along. the  dorsura 
jf  the  foot.  The  integument  alone  should  be  reflected. 

The  front  of  the  leg  will  be  found  encased  by  a  strong, 
glistening  fascia,  continuous  with  the  fascia  lata  of  the 
;high  ;  upon  the  inner  side  of  this  will  be  found  the  internal 
iphena  vein,  and,  at  the  junction  of  the  middle  and  lower 
third,  the  continuation  of  the  musculo-cutaneous  branch  of 
peroneal  nerve  will  be  seen  emerging  through  an  aper- 
Lure  in  the  fascia. 

The  internal  saphena  vein  commences  at  the  great  toe, 

icl  passes  up  along  the  inner  side  of  the  leg,  and  behind 
the  inner  condyle,  to  the  saphenous  opening  in  the  upper 
part  of  the  anterior  femoral  region  (p.  196),  where  it  termi- 
nates in  the  femoral  vein. 

The  musculo-cutaneous  nerve,  after  its  division  from  the 
peroneal  at  the  head  of  the  fibula,  passes  downward  between 
the  peronei  muscles  and  the  extensor  longus  digitorum, 
to  emerge  through  a  distinct  foramen  in  the  fascia  on  the 
front  of  the  leg,  at  about  the  union  of  its  middle  and  lower 
third ;  it  then  divides  into  two  branches,  called  the  peroneal 
cutaneous  ;  these  pass  down  superficially,  and  at  the  toes 
divide  again  into  branches,  distributed  to  their  sides,  ex- 
cept the  outer  side  of  the  little  toe. 

On  the  dorsum  of  the  foot,  the  termination  of  the  anterior 
tibial  nerve  (p.  240)  will  be  found,  accompanying  the  dor- 
salis  pedis  artery  in  the  first  interosseous  space ;  this  nerve 
generally  supplies  the  great  toe,  and  the  outer  side  of  the 
next; -it  anastomoses  with  the  peroneal  cutaneous  nerves. 

Along:  the  outer  border  of  the  foot  will  be  found  the 


238   ANATOMY  OP  THE  LOWER  EXTREMITY. 

termination  of  the  external  saphena  nerve,  which  supplies 
the  little  toe,  and  sometimes  the  outer  side  of  the  next. 
The  distribution  of  the  nerves  to  the  toes  constantly  varies. 
The  fascia  of  the  leg,  extending  across  from  the  anterioi 
surface  of  the  tibia  to  the  fibula,  is  extremely  dense,  and, 
at  the  upper  part  of  the  leg,  binds  down  and  is  closel; 
adherent  to  the  muscles  beneath,  some  of  their  fibres 
originating  from  it.  At  the  ankle,  it-  forms  the  anterioi 
annular  ligament;  this  is  a  thickened  portion,  crossing 
from  the  external  malleolus  and  upper  surface  of  the  os 
calcis  to  the  internal  malleolus,  and  the  borders  of  which 
are  imperfectly  defined  ;  it  contains  three  sheaths  for  the 
tendons  of  the  muscles  which  pass  down  from  the  leg  to 
the  dorsum  of  the  foot,  viz.,  one  for  the  tibialis  anticns, 
one  for  the  extensor  proprius  pollicis,  and  the  third  for  the 
extensor  longus  digitorum  and  peroneus  tertius  muscle. 
The  under  portion  of  the  sheath  for  the  extensor  proprius 
pollicis  muscle  converts  that  part  of  the  ligament  into  a 
sort  of  sling,  and  is  attached  to  the  os  calcis  under  the 
name  of  ligament  of  Retzius. 

The  fascia  of  the  leg  should  be  removed  by  detaching  it  from  below 
upward  ;  where  it  becomes  blended  with  the  bellies  of  the  muscles,  it 
should  be  left  in  connection  with  them.  The  annular  ligament  is  not 
to  be  removed.  The  muscles  of  this  region  should  be  separated  from 
each  other  by  following  them  up  from  their  tendons. 

The  TIBIALIS  ANTICUS  MUSCLE  lies  along  the  side  of  the 
tibia,  arising  from  the  upper  two  thirds  of  its  inner  surface 
and  from  the  interosseous  membrane ;  its  tendon  passes 
through  a  separate  sheath  in  the  annular  ligament,  and  is 
inserted  into  the  side  of  the  internal  cuneiform  bone  and 
the  head  of  the  first  metatarsal  bone. 

The  EXTENSOR  PROPRIUS  POLLICIS  is  a  thin  muscle, 
covered  in  by  the  tibialis  anticus  on  one  side  and  the 
extensor  longus  digitorum  on  the  other ;  it  arises  from  the 
middle  third  of  the  fibula,  and  its  tendon,  which  runs  along 
the  anterior  border  of  the  muscle,  receiving  the  fibres  in  a 
penniform  manner,  passes  through  a  separate  sheath  in  the 
annular  ligament,  and  is  inserted  into  the  base  of  the  second 
phalanx  of  the  great  toe. 

The  EXTENSOR  LONGUS  DIGITORUM  arises  from  the  upper 
half  of  the  fibula,  from  the  head  of  the  tibia  and  from  the 
interosseous  membrane  ;  its  fibres  are  inserted  in  a  penni- 
form manner  into  three  tendons  which  commence  upon  the 


FRONT  OF  LEG  AND  DORSUM  OF  FOOT.   239 

anterior  border  of  the  muscle ;  these  pass  through  the 
annular  ligament,  and  on  the  dorsum  of  the  foot  the  inner 
tendon  divides  into  two,  thus  making  four  tendons  destined 
to  all  thejtoes  except  the  great  toe.  The  tendons  of  the 
extensor  brevis  are  inserted  into  the  outer  side  of  each  of 
these  tendons,  with  the  exception  of  the  one  to  the  little 
toe,  and  the  expanded  tendon  thus  formed  divides,  as  in 
the  hand,  into  three  slips,  the  central  one  of  which  is  in- 
serted into  the  second  phalanx,  and  the  two  lateral  into 

sides  of  the  last  phalanx. 
The  EXTENSOR  BREVIS   DIGITORUM,  covered  in  by  the 
melons  of  the  extensor  longus  and  peroneus  tertius  mus- 
5,  lies  upon  the  dorsum  of  the  foot,  and  consists  of  a 
lall  flat  belly  arising  from  the  outside  of  the  os  calcis, 
id  from  which  emanate  four  tendons ;  the  first  crosses  the 
lorsalis  pedis  artery,  and  is  inserted  into  the  first  phalanx 
of  the  great  toe,  the  other  three  terminate  by  blending 
rith  the  outer  side  of  the  tendons  of  the  extensor  longus 
niscle. 

The  PERONEUS  TERTIUS  MUSCLE  is  in  reality  a  part  of  the 
:tensor  longus  ;  it  arises  from  the  lower  third  of  the  fibula 
a  thin  layer  of  fibres,  which  terminate  in  a  round  tendon 
lat  passes  under  the  annular  ligament  in  the  same  sheath 
with  the  extensor  longus,  and  is  inserted  into  the  base  of 
the  metatarsal  bone  of  the  fifth  toe.  It  is  not  imfrequently 
wanting. 

Upon  separating  the  tibialis  anticus  and  the  extensor 
longus  muscles,  the  anterior  tibial  artery  will  be  found, 
lying  deep  in  the  upper  part  of  the  leg,  but  more  superficial 
lower  down.  After  its  division  from  the  popliteal  artery, 
it  pursues  a  short  course  posteriorly,  to  the  space  between 
the  fibula  and  tibia,  and  becomes  anterior  by  passing 
through  the  interval  left  at  the  upper  part  of  the  interos- 
seous  membrane,  upon  which  it  descends,  in  company  with 
the  anterior  tibial  nerve  and  two  large  venae  comites ;  in 
the  upper  part  of  its  course  it  lies  between  the  tibialis 
anticus  and  the  extensor  longus  muscles ;  lower  down  it 
lies  between  the  tibialis  anticus  tendon  and  that  of  the 
extensor  proprius  pollicis,  passes  under  the  annular  liga- 
ment, and  on  the  back  of  the  foot  becomes  the  dorsalis 
pedis  artery.  At  its  upper  part  it  sends  a  recurrent  branch 
upward,  which  perforates  the  head  of  the  tibialis  anticus 
muscle,  and  anastomoses  with  the  inferior  articular  branches 
of  the  popliteal ;  in  its  course  between  the  muscles  it  gives 


240   ANATOMY  OP  THE  LOWER  EXTREMITY. 

off  numerous  muscular  twigs,  and  at  the  ankle-joint  ai 
external  and  internal  malleolar  branch ;  these  supply  th< 
parts   about  the  joint,  anastomosing  with  the  calcanes 
branches  of  the  posterior  tibial  and  peroneal  arteries. 

The  anterior  peroneal  artery,  coming  from  the  back 
the  leg,  passes  through  an  aperture  in  the  lower  part  of  the 
interosseous  membrane,  and  is  distributed  in  front  of  the 
fibula  to  the  dorsum  and  outer  part  of  the  foot,  anastomos- 
ing with  the  malleolar  branches  of  the  anterior  tibial. 

The  anterior  tibial  nerve,  one  of  the  divisions  of  the 
peroneal  nerve,  having  passed  through  the  opening  in  the* 
upper  part  of  the  interosseous  membrane,  will  be  found 
emerging  from  under  the  belly  of  the  extensor  longus  mus- 
cle, to  accompany  the  anterior  tibial  artery  which  lies  upon 
its  outer  side  ;  on  the  dorsum  of  the  foot  it  is  distributed 
as  has  been  described. 

The  musculo-cutaneous  nerve,  the  other  division  of  the 
peroneal  nerve,  after  curving  round  the  head  of  the  fibula 
and  passing  beneath  the  fascia  of  the  leg,  lies  between  the 
extensor  longus  and  the  peronei  muscles ;  it  then  pierces 
the  fascia,  becomes  subcutaneous,  and  is  distributed  as  has 
been  described. 

The  dorsalis  pedis  artery  lies  upon  the  outer  side  of  the 
tendon  of  the  extensor  proprius  pollicis;  it  is  accompanied 
by  the  anterior  tibial  nerve ;  it  distributes  some  branches 
to  the  tarsus,  called  tarsal,  and  then  forms  an  arch  over 
the  bases  of  the  metatarsal  bones  ;  this  arch  gives  off  three 
interosseous  branches  which,  at  the  commissures  of  the 
third,  fourth,  and  fifth  toes,  divide  into  digital  branches, 
to  supply  the  sides  of  the  toes.  At  each  end  of  the  inter- 
osseous spaces  these  arteries  are  joined  by  perforating 
branches  from  the  sole  of  the  foot.  At  the  base  of  the  first 
interosseous  space,  the  dorsalis  pedis  penetrates  to  the  sole 
of  the' foot,  to  unite,  under  the  name  of  the  communicating 
artery,  with  the  termination  of  the  plantar  arch ;  before 
disappearing  it  gives  off  the  dorsalis  hallucis  branch,  which 
passes  forward  and  is  distributed  to  the  great  toe  and  the 
inner  side  of  the  next  toe. 

The  DORSAL  INTEROSSEOUS  MUSCLES  arise  by  two  heads 
from  the  sides  of  the  bases  of  adjoining  metatarsal  bones ; 
they  are  inserted  into  the  bases  of  the  first  phalanges  of 
the  toes,  and  into  the  expansion  of  the  extensor  tendons ; 
the  first  interosseous  muscle  being  inserted  into  the  inside 
of  the  second  toe,  and  the  three  others  into  the  outsides  of 
the  second,  third,  and  fourth  toes. 


BACK    OF    THE    LEG.  241 

DISSECTION  XII. 

BACK   OF   THE    LEG. 

The  dissection  of  the  back  of  the  leg  is  to  be  commenced  by  an  in- 
cision from  the  popliteal  space  to  the  heel.  The  integument  is  to  be 
reflected  with  care,  as  there  are  several  superficial  structures  to  be 
examined. 

The  external  saphena  vein,  commencing  on  the  outer 
border  of  the  foot,  ascends  along  the  outside  of  the  tendo 
Achillis,  upon  the  belly  of  the  gastrocnemius  muscle  and 
between  its  two  heads,  to  the  popliteal  space,  where  it 
enters  the  popliteal  vein. 

The  external  saphena  nerve,  formed  from  the  communi- 
cans  peronei  and  poplitei,  which  unite  at  a  variable  distance 
down  the  leg,  or  occasionally,  in  the  case  of  their  non-union, 
iing  one  of  these  nerves  itself,  lies  at  the  side  of  the  ex- 
jrnal  saphena  vein  along  the  outer  border  of  the  tendo 
.chillis ;  it  curves  around  the  external  malleolus  and  is 
Listributed  to  the  outer  border  of  the  foot  and  little  toe. 
The  muscles  of  the  leg  are  arranged  in  two  layers,  super- 
nal and  deep;  the  superficial  layer  constitutes  the  "calf 
the  leg." 

The  GASTROCNEMIUS  MUSCLE,  the  first  muscle  of  the 
superficial  layer,  arises  by  two  heads,  of  which  the  inner 
is  the  larger,  from  the  surface  of  bone  above  each  condyle 
of  the  femur ;  these  heads  converge  and  form  the  lower 
boundary  of  the  popliteal  space,  and  are  situated  inside 
the  tendons  forming  the  ham-strings ;  they  are  each  sup- 
plied with  an  arterial  branch,  the  sural,  from  the  popliteal 
artery.  The  large  muscular  belly  of  the  gastrocnemius 
terminates  in  a  brilliant  aponeurosis,  finally  converted  into 
a  -large,  round  tendon,  called  the  tendo  Achillis,  which  is 
inserted  into  the  lower  part  of  the  posterior  surface  of  the 
os  calcis  ;  this  tendon,  for  some  distance  above  its  insertion, 
is  common  to  this  muscle  and  to  the  soleus  which  lies  be- 
neath it. 

The  small  rounded  tendon  of  the  plantaris  muscle,  running  along 
the  inside  of  the  tendo  Achillis,  to  which  it  is  more  or  less  adherent, 
should  be  sought  for  and  isolated,  that  it  may  not  be  cut  across  iu 
dividing  the  gastrocnemius. 

The  gastrocnemius  should  be  separated  along  its  borders  from  the 
soleus,  in  order  to  determine  the  line  of  division  between  them  ;  H 
21 


242   ANATOMY  OF  THE  LOWER  EXTREMITY. 

may  then  be  cut  across  just  below  the  union  of  its  heads,  and  the  two 
halves  reflected. 

In  dissecting  up  the  heads  of  the  gastrocnemius,  the 
strong  character  of  their  osseous  attachment  will  be  seen. 
A  sjnnovial  bursa  is  sometimes  found  between  the  muscle 
and  the  condyle  on  one  or  both  sides,  and  a  sesamoid  bone 
is  occasionally  developed  in_the  head  attached  to  the  outer 
condyle. 

The  PLANTARIS  MUSCLE  arises  from  the  outer  condyle  of 
the  femur  in  common  with  the  under  part  of  the  outer 
head  of  the  gastrocnemius ;  it  forms  a  short  belly,  from 
two  to  four  inches  in  length,  terminating  in  a  long,  slender 
tendon  which  crosses  obliquely  between  the  gastrocnemius 
and  soleus  muscles,  and  passing  downward  along  the  inner 
side  of  the  tendo  A  chillis,  is  inserted  by  the  side  of  that 
tendon  into  the  calcaneum.  It  is  not  always  easy  to  sepa- 
rate it  from  the  tendo  Achillis  at  its  lower  part. 

The  SOLEUS  MUSCLE  arises  from  the  head  and  upper  half 
of  the  fibula,  and  from  the  middle  of  the  shaft  of  the  tibia ; 
it  forms  an  elliptical-shaped  belly,  and  joins  the  tendo 
Achillis  some  distance  below  its  commencement.  A  syno- 
vial  bursa  is  placed  between  the  tendo  Achillis  and  the 
calcaneum  above  the  point  of  its  insertion,  and  a  consider- 
able interspace,  filled  with  fat  and  cellular  tissue,  exists 
between  it  and  the  layer  of  muscles  beneath. 

The  tendo  Achillis  is  to  be  divided,  and  the  soleus  and  plantaris 
entirely  removed  ;  in  doing  this,  it  must  be  remembered,  that  the  deep 
vessels  and  nerves,  covered  in  by  a  fascia,  lie  between  these  muscles 
and  those  beneath. 

A  stout  layer  of  fascia  covers  in  the  deep  muscles  and 
vessels ;  it  extends  from  the  popliteal  space  to  the  ankle- 
joint,  and  is  attached  to  the  fibula  on  one  side,  and  the 
tibia  on  the  other. 

The  popliteal  artery  will  be  found  dividing  into  the  ante- 
rior and  posterior  tibial  arteries,  and  the  course  of  the 
anterior  tibial  artery,  to  the  point  where  it  perforates  the 
interosseous  membrane,  will  now  be  seen. 

The  posterior  tibial  artery  descends  the  leg  on  the  side 
of  the  tibia,  and,  at  the  lower  part  of  its  course,  becomes 
comparatively  superficial ;  it  runs  along  the  tendo  Achillis, 
to  the  concavity  formed  by  the  internal  malleolus  and  os 
calcis,  where  it  divides  into  the  plantar  arteries,  which  will 
be  seen  in  the  dissection  of  the  sole  of  the  foot.  It  gives  off 


all 

: 


BACK    OP    THE    LEG.  243 

in  its  course  numerous  muscular  branches,  some  of  which 
were  divided  in  removing  the  superficial  layer  of  muscles; 
others  will  be  seen  going  to  the  deep  layer ;  a  nutrient  artery, 
to  the  tibia,  may  sometimes  be  found,  if  the  subject  is  well 
injected.  The  principal  branch  of  the  posterior  tibial  artery 
is  the  peroneal. 

The  peroneal  artery  arises  some  distance  from  the  com- 
mencement of  the  posterior  tibial,  and  passes  downward 
along  the  inner  border  of  the  fibula;  in  the  lower  third  of 
the  leg  it  divides  into  two  branches:  one  of  them,  the 
anterior,  perforates  the  interosseous  membrane,  and  is  dis- 
tributed in  front  of  the  external  malleolus;  the  posterior 
division  continues  downward  to  the  outside  of  the  os  calcis, 
where  it  breaks  up  into  external  calcanear  branches.  The 
peroneal  and  posterior  tibial  arteries  present  frequent  varia- 
tions of  distribution  arid  size ;  one  or  the  other  is  occasion- 
ally absent,  and  they  sometimes  communicate  with  each 
ther  by  means  of  a  short,  though  large,  transverse  anas- 

mosis. 

The  posterior  tibial  nerve  accompanies  the  posterior 
ibial  artery,  lying  first  upon  its  inside,  and  then  upon  its 
outside.  At  the  inner  malleolus,  it  divides  into  two 
branches,  the  internal  and  external  plantar.  In  its  course, 
it  gives  off  muscular  branches,  one  of  which  accompanies 
the  peroneal  artery ;  at  the  heel,  it  gives  off  the  plantar 
cutaneous  branches,  distributed  to  the  integument  of  the 
side  of  the  heel. 

The  POPLITEUS  is  a  short  muscle  situated  just  below  the 
knee-joint;  arising  from  the  outer  side  of  the  external  con- 
dyle,  it  passes  obliquely  downward,  to  be  inserted  into 
the  surface  of  the  tibia,  above  the  oblique  line,  known  as 
the  popliteal. 

The  FLEXOR  LONGUS  DIGITORTJM  PEDIS  arises  from  the  sur- 
face of  the  tibia,  below  the  popliteus  muscle,  and  passing 
behind 'the  internal  malleolus,  through  a  sheath  in  the 
internal  annular  ligament,  between  the  tendons  of  the 
tibialis  posticus  and  the  flexor  longus  pollicis,  enters  the 
sole  of  the  foot,  and  divides  into  four  tendons,  inserted 
into  the  last  phalanges  of  all  the  toes,  except  the  great  toe, 
as  will  be  seen  hereafter. 

The  FLEXOR  LONGUS  POLLICIS  PEDIS  lies  upon  the  outer 
side  of  the  leg,  and  arises  from  the  lower  two  thirds  of  the 
fibula,  and  from  the  interosseous  membrane;  its  tendon 
curves  around  the  internal  malleolus,  passes  through  a 


244        ANATOMY    OF    THE    LOWER    EXTREMITY. 

sheath  of  the  internal  annular  ligament,  below  the  tubercl< 
of  the  os  calcis,  and,  entering  the  sole  of  the  foot,  is  insertc 
into  the  last  phalanx  of  the  great  toe.  The  posterior  tibh 
nerve  lies  along  the  inner  side  of  this  muscle,  and  the  pen 
neal  vessels  are  in  part  concealed  by  it. 

The  TIBIALTS  POSTICUS  MUSCLE  occupies  a  position  be- 
tween the  two  bones  of  the  leg,  and  between  the  two  mus- 
cles last  described.  It  arises  from  nearly  the  whole  length 
of  both  tibia  and  fibula,  and  from  the  interosseous  mem- 
brane ;  its  origin  superiorly  forms,  as  it  were,  two  heads, 
between  which  passes  the  anterior  tibial  artery;  its  tendon 
curves  around  the  internal  malleolus,  passing  through  the 
sheath  in  the  internal  annular  ligament  which  is  nearest 
the  malleolus,  and  enters  the  sole  of  the  foot,  to  be  inserted 
into  the  scaphoid  and  external  cuneiform  bones,  and  into 
the  base  of  the  first  metatarsal  bone. 

Along  the  outer  border  of  the  leg,  and  upon  the  fibula, 
will  be  found  two  muscles,  the  peroneus  longus  and  pero- 
neus  brevis. 

The  PERONEUS  LONGUS  MUSCLE  arises  from  the  head  and 
upper  part  of  the  surface  of  the  fibula,  and  terminating  in 
a  long  tendon,  curves  around  the  external  malleolus,  and 
passes  through  the  sheath  of  the  external  annular  liga- 
ment; entering  the  sole  of  the  foot,  it  crosses  obliquely 
forward  to  be  inserted  into  the  base  of  the  metatarsal  bone 
of  the  great  toe.  The  musculo-cutaneous  nerve  lies  be- 
tween this  muscle  and  the  extensor-longus  digitornm. 

The  PERONEUS  BREVIS  lies  beneath  the  preceding  muscle, 
and  arises  from  the  lower  half  of  the  outer  surface  of  the 
fibula;  its  fibres  are  inserted  in  a  penniform  manner  into  a 
tendon  which  passes  beneath  the  external  annular  ligament, 
with  the  peroneus  longus,  and  is  inserted  into  the  base  of 
the  metatarsal  bone  of  the  fifth  toe. 

The  INTERNAL  ANNULAR  LIGAMENT  confines  the  tendons 
which  curve  around  the  inner  ankle  from  the  back  of  the 
leg ;  it  stretches  across  from  the  tip  of  the  internal  mal- 
leolus to  the  side  of  the  os  calcis,  and  contains  three  com- 
partments, lined  by  synovial  membrane,  which  transmit 
the  tendons  of  the  tibialis  posticus,  flexor  longus  digitorum 
pedis,  and  flexor  longus  pollicis,  in  the  order  in  which  they 
have  been  mentioned,  that  of  the  tibialis  posticus  being 
nearest  the  malleolus. 

The  EXTERNAL  ANNULAR  LIGAMENT  stretches  across 
from  the  tip  of  the  external  malleolus  to  the  side  of  the  os 


SOLE    OP    THE    FOOT.  245 

calcis,  and  contains  a  single  compartment  lined  with 
synovial  membrane,  through  which  pass  the  tendons  of 
the  peroneus  longus  and  brevis  muscles. 


DISSECTION  XIII. 

SOLE  OF  THE  FOOT. 

The  density  of  the  cuticle,  the  thickness  of  the  fat  and  areolar  tis- 
le  superficially,  and  the  number  and  smallness  of  the  muscles,  with 
the    amount  of  aponeurotic   structure  which  belongs  to  the  region, 
wilder  the  dissection  of  the  sole  of  the  foot  a  slow  and  tedious  pro- 
A  block  should  be  put  under  the  instep,  and  as  the  foot,  by  its 
nvn  weight,  offers  no  impediment  to  constant  unsteadiness,  it  should 
fixed  to  the  table  by  hooks.     An  incision  is  to  be  made  down  the 
liddle  of  the  sole,  from  the  heel  to  the  commissure  of  the  toes;  this 
should  penetrate  to  the  plantar  fascia  ;  the  integument,  with  the  fat, 
should  then  be  removed,  and,  as  a  preliminary  step,  this  fascia  should 
cleanly  dissected,  and  the  deposits  of  fat  removed  from  its  inter- 
tices,  carefully  looking  out  for  the  nerves  which  nearly  resemble  its 
ibres  in  color. 

The  plantar  fascia  is  a  thick  aponeurosis  which  expands 
>ver  the  whole  sole  of  the  foot,  lying  between  the  muscles 
md  the  adipose  tissue  beneath  the  integument ;  it  is  thicker 
in  the  centre  than  at  the  sides  of  the  foot,  and  dividing 
into  slips  anteriorly,  is  attached  to  the  base  of  the  first 
>halanx  of  each  toe  by  lateral  processes,  between  which 
LSS  the  flexor  tendons ;  these  are  crossed  by  some  trans- 
^erse  bands  of  fibres  which  form  the  rudimentary  web  of 
Lhe  commissures  of  the  toes  ;  between  the  slips,  the  nerves 
destined  to  the  toes,  and  the  lumbricales  muscles  will  be 
found. 

The  plantar  fascia  may  he  removed  by  dividing  it  transversely  and 
dissecting  it  up  from  the  subjacent  attachments  ;  this  will  expose  the 
muscles  beneath.  In  direct  relation  with  the  central  portion  of  the 
plantar  fascia  is  the  flexor  brevis  digitorum. 

The  FLEXOR  BREVIS  DIGITORUM  PEDIS  arises  from  the 
under  side  of  the  os  calcis  and  from  the  plantar  fascia ;  it 
divides  into  four  tendons,  which  are  inserted  into  the  bases 
of  the  second  phalanges  of  the  outer  four  toes ;  they  are 
each  perforated  to  permit  the  passage  through  them  of  the 
tendons  of  the  long  flexor,  which  is  inserted  into  the  last 
phalanx. 

21* 


246   ANATOMY  OF  THE  LOWER  EXTREMITY. 

The  sheaths  of  the  flexor  tendons  consist  of  transverse 
fibrous  bands  which  hold  the  tendons  down  upon  the 
phalanges;  though  similar  to  those  of  the  fingers,  they  are 
not  so  distinct  nor  so  well  developed. 

The  ABDUCTOR  POLLICIS  PEDIS  lies  upon  the  side  of  the 
great  toe ;  it  arises  by  two  heads,  which  are  not,  however, 
well-marked  divisions ;  one  springs  from  the  internal  annular 
ligament  which  covers  in  the  vessels  and  tendons  below 
the  inner  malleolus,  the  other  from  the  inner  tuberosity  of 
the  os  calcis.  Between  these  heads  pass  the  plantar  ves- 
sels, nerves,  and  tendons.  It  is  inserted,  after  uniting  with 
the  tendon  of  the  flexor  breyis  pollicis,  into  the  base  of  the 
first  phalanx  of  the  great  toe. 

The  ABDUCTOR  MINIMI  DIGITI  PEDIS  is  placed  along  the 
outer  edge  of  the  foot ;  it  arises  from  the  external  surface 
of  the  os  calcis,  and  from  the  plantar  fascia  which  covers 
it,  and  is  inserted  into  the  base  of  the  first  phalanx  of  the 
little  toe. 

The  flexor  brevis  digitorum  is  separated  from  the  mus- 
cles on  each  side  of  it  by  strong  intermuscular  septa ;  the 
inner  of  these  is  perforated  by  the  internal  plantar  nerve 
and  by  the  tendon  of  the  flexor  longus  pollicis ;  the  outer 
by  a  nerve  and  artery  destined  to  the  little  toe. 

The  flexor  brevis  digitorum  and  abductor  minimi  digiti  should  be 
divided,  and  their  two  ends  reflected  ;  the  tendons  of  the  long  flexor, 
with  the  plantar  vessels  and  nerves,  will  then  be  exposed,  and  should 
be  cleared  from  the  superfluous  areolar  tissue  which  invests  them. 

The  posterior  tibial  artery,  on  entering  the  sole  of  the 
foot,  divides  into  the  internal  and  external  plantar  arteries. 

The  internal  plantar  artery  passes  between  the  abductor  pollicis  and 
flexor  brevis  digitorum  to  the  great  toe  ;  it  gives  off  small  muscular 
branches,  and  terminates  in  supplying  the  sides  of  the  great  toe  ; 
it  anastomoses  with  the  digital  branches  of  the  external  plantar  artery, 
and  the  communicating  branch  of  the  dorsalis  pedis. 

The  external  plantar  artery  is  larger  than  the  internal  ;  it  passes 
obliquely  beneath  the  flexor  brevis  digitorum  to  the  base  of  the  fifth 
metatarsal  bone,  and  then  curves  transversely  across  the  foot,  dipping 
beneath  the  deeper  muscles,  to  the  first  interosseous  space,  which  it 
penetrates  to  anastomose  with  the  dorsalis  pedis  artery. 

The  nerves  of  the  sole  of  the  foot  are  derived  from  the 
posterior  tibial  nerve,  which,  at  the  inner  malleolus,  divides 
into  external  and  internal  plantar  branches. 


SOLE    OF    THE    FOOT.  247 

The  internal  plantar  nerve  is  the  larger  of  the  two,  and  runs  along 
the  edge  of  the  abductor  pollicis  muscle,  and  divides  opposite  the 
bases  of  the  metatarsal  bones,  into  four  digital  branches  which  sup- 
ply, by  bifurcating,  both  sides  of  the  first,  second,  and  third  toes,  and 
the  inside  of  the  fourth  toe ;  it  also  gives  off  small  muscular  branches. 

The  external  plantar  nerve  accompanies  the  external  plantar  artery 
as  far  as  the  fifth  metatarsal  space,  where  it  sends  off  a  large  muscu- 
lar branch,  and  continues  on  in  two  divisions,  which  supply  the  outer 
edge  of  the  foot,  the  little  toe,  and  the  outside  of  the  next,  which  is  un- 
supplied  by  the  internal  plantar. 

In  the  second  layer  of  muscles  are  found  the  tendons  of 
the  flexor  longus  digitorum  and  flexor  longus  pollicis  mus- 
cles, the  bellies  of  which  have  been  already  dissected  upon 
the  back  of  the  leg  (p.  243).  The  tendon  of  the  flexor 
longus  digitorum  passes  to  the  middle  of  the  sole  of  the 
foot,  and  is  there  joined  by  a  tendinous  process  from  the 
flexor  longus  pollicis,  and  by  the  musculus  accessorius;  it 
then  divides  into  four  tendons  for  the  outer  four  toes ;  these 
perforate  the  tendons  of  the  flexor  brevis,  and  are  held 
down  to  the  phalanges  by  ligamenta  brevia,  like  those  of 
the  tendons  of  the  fingers  (p.  154).  Their  insertion  and  that 
of  the  flexor  longus  pollicis  have  previously  been  given. 

The  LUMBRICALES  MUSCLES  are  four  small  muscles  arising 
from  the  tendons  of  the  long  flexor,  and  inserted  into  the 
expansions  of  the  extensor  tendons,  and  the  inner  sides  of 
the  first  phalang-es  of  all  the  toes  except  the  great  toe. 
They  are  subject  to  variations. 

The  MUSCULUS  ACCESSORIUS,  or  MASSA  CARNEA  JACOBI 
SYLVII,  arises  by  two  heads,  one  from  the  concave,  inner 
side  of  the  os  calcis,  and  the  other  from  its  under  surface, 
and  is  inserted  into  the  tendon  of  the  flexor  longus  digi- 
torum, just  as  it  breaks  up  into  its  four  digital  divisions. 

The  tendons  of  the  flexor  longus  must  be  divided,  and,  with  their 
accessory  muscles,  reflected. 

The  FLEXOR  BREVIS  POLLICIS  PEDIS  arises  from  the 
cuboid  and  external  cuneiform  bones ;  it  lies  upon  the  me- 
tatarsal bone  of  the  great  toe,  and  is  inserted  by  two  heads 
into  the  base  of  its  first  phalanx  ;  the  outer  head  joins  with 
the  tendon  of  the  abductor  pollicis,  and  the  inner  head  with 
that  of  the  adductor  pollicis ;  a  sesamoid  bone  is  usually 
found  in  each  of  these  heads ;  the  tendon  of  the  flexor 
longus  pollicis  passes  between  them. 

The  ADDUCTOR  POLLICIS  PEDIS  is  placed  obliquely  in  the 
sole  of  the  foot ;  it  arises  from  the  cuboid  bone,  the  bases 


248   ANATOMY  OF  THE  LOWER  EXTREMITY. 

of  the  third  and  fourth  metatarsal  bones,  and  from  the 
sheath  of  the  tendon  of  the  peroneus  longus  muscle ;  it 
forms  a  short  belly,  and  is  inserted,  with  the  inner  head  of 
the  flexor  brevis  pollicis,  into  the  base  of  the  first  phalanx 
of  the  great  toe.  A  sesamoid  bone  is  usually  found  in  the 
insertion  of  its  tendon. 

The  FLEXOR  BREVIS  MINIMI  DIGITI  PEDIS  arises  from 
the  base  of  the  metatarsal  bone  of  the  fifth  toe  and  the 
sheath  of  the  tendon  of  the  peroneus  longus,  and  is  inserted 
into  the  base  of  the  first  phalanx  of  the  little  toe. 

The  TRANSVERSALIS  PEDIS  is  a  thin  layer  of  muscular 
slips,  lying  transversely  across  the  anterior  portions  of  the 
metatarsal  bones ;  it  arises  from  the  heads  of  the  metatar- 
sal bones  of  the  four  lesser  toes,  and  is  inserted  into  the 
tendon  of  the  adductor  pollicis ;  sometimes  there  is  but 
one  slip ;  there  are  rarely  so  many  as  four. 

The  adductor  pollicis  and  flexor  brevis  minimi  digiti  are  to  be  di- 
vided near  their  origins,  and  turned  forward  on  to  the  toes  ;  this  will 
expose  the  plantar  arch. 

The  plantar  arch  is  the  continuation  of  the  external 
plantar  artery  from  the  base  of  the  fifth  metatarsal  bone 
to  its  anastomosis  with  the  communicating  branch  of  the 
dorsalis  pedis ;  it  lies  upon  the  interosseous  muscles,  and 
gives  off  four  digital  branches  to  the  toes;  the  first  goes  to 
the  outer  side  of  the  little  toe ;  the  others,  dividing  at  the 
commissures,  supply  the  contiguous  sides  of  the  outer 
three  toes  and  the  outer  side  of  the  second.  At  each  end 
of  the  interosseous  spaces,  the  digital  arteries  send  small 
branches  called  posterior  and  anterior  perforating,  to  the 
interosseous  branches  of  the  dorsalis  pedis  artery.  The 
communicating  branch  of  the  dorsalis  pedis  enters  the  sole 
of  the  foot,  and,  uniting  with  the  internal  plantar  artery 
and  the  termination  of  the  plantar  arch,  gives  off  the  branch 
which  supplies  both  sides  of  the  great  toe. 

The  PLANTAR  INTEROSSEOUS  MUSCLES  are  three  in  num- 
ber; they  arise  from  the  under  sides  of  the  metatarsal 
bones,  and  are  inserted  into  the  inner  sides  of  the  bases  of 
the  first  'phalanges  of  the  outer  three  toes,  and  into  the 
expansions  of  the  extensor  tendons. 

The  tendon  of  the  tibialis  posticus  (p^244)  may  now  be 
traced  to  its  termination  ;  it  passes  forward  over  the  articu- 
lation of  the  astragalus  and  scaphoid  bones  to  be  inserted 
into  the  latter,  into  the  base  of  the  first  metatarsal  bone, 


LIGAMENTS    OP    THE    PELVIS,   ETC.  249 

and  also  into  the  external  cuneiform  bone;  a  sesamoid 
bone  is  usually  found  in  its  tendon. 

The  tendon  of  the  peroneus  longus  (p.  244)  passes  ob- 
liquely across  the  foot  to  the  base  of  the  metatarsal  bone 
of  the  great  toe,  into  which  it  is  inserted  ;  as  it  turns  round 
the  cuboid  bone  its  tendon  becomes  thickened  and  fibro- 
cartilaginous,  and  sometimes  contains  a  sesamoid  bone ;  it 
is  enveloped  with  a  sheath  formed  by  the  ligaments  of  the 
tarsal  bones,  and  lined  by  a  synovial  membrane. 


DISSECTION  XIV. 

LIGAMENTS   OF   THE   PELVIS   AND   LOWER   EXTREMITY. 

The  pelvis  is  connected  with  the  vertebral  column  by 
ligaments  similar  to  those  uniting  one  vertebra  to  another, 
with  the  addition  of  two  special  ligaments,  the  lumbo- 
sacral  and  the  ilio-lumbar. 

The  lumbo-sacral  ligament  is  a  stout,  triangular  bundle 
)f  fibres  springing  from  the  tip  of  the  transverse  process 
>f  the  last  lumbar  vertebra,  and  expanding,  fan-shaped,  to 
>e  inserted  into  the  posterior  part  of  the  upper  border  of 
jhe  sacrum. 

The  ilio-lumbar  ligament  extends  between  the  tip  of  the 
transverse  process  of  the  last  lumbar  vertebra  and  the  crest 
of  the  ilium,  just  above  the  sacro-iliac  articulation. 

The  sacrum  and  the  coccyx  are  united  by  an  anterior 
and  posterior  common  ligament,  and  by  intervening  fibro- 
cartilaginous  dixks;  in  adults,  the  bones  are,  however, 
usually  co-ossified. 

The  sacrum  and  ilium  are  united  by  cartilage,  and  by 
anterior  and  posterior  sacro-iliac  ligaments,  at  the  sacro- 
iliac  synchondrosis,  and  by  the  sacro-ischiatic  ligaments 
inferiorly.  • 

The  anterior  sacro-iliac  ligament  is  a  transverse  band  of 
fibres  covering  the  anterior  aspect  of  the  articulation. 

The  posterior  sacro-iliac  ligament  is  composed  of  stout 
bundles  of  fibres  passing  between  the  first  two  bones  of  the 
sacrum  and  the  rough  surface  at  the  posterior  border  of  the 
ilium. 

The  greater  sacro-ischiatic  ligament  passes  from  the  side 
of  the  sacrum  and  coccyx  to  the  tuberosity  of  the  ischiurn. 


250        ANATOMY    OP    THE    LOWER    E.XTREMITY. 

The  lesser  sacro-ischiatic  ligament  arises  from  the  side 
of  the  sacrum  and  coccyx,  and  is  inserted  into  the  spine  o1 
the  ischium.  These  two  ligaments  convert  the  space  be- 
tween the  sacrum  and  os  innominatum  into  two  apertures, 
called  the  greater  and  lesser  sacro-ischiatic  foramina, 
through  which  issue  the  nerves,  arteries,  and  muscles  from 
the  interior  of  the  pelvis. 

The  union  of  the  pubic  bones  in  front  is  called  the  sym- 
physis pubes. 

The  anterior  pubic  ligament  consists  of  horizontal  and 
oblique  fibres,  interlacing  in  front  of  the  symphysis.  The 
periosteum  constitutes  the  posterior  pubic  ligament. 

The  superior  pubic  ligament  covers  the  surface  of  the 
bones  superiorly,  and  blends  with  the  tendinous  insertions 
of  the  abdominal  muscles. 

The  sub-pubic  ligament  is  a  fibrous  arch  attached  to  the 
bones  of  the  pubes  inferiorly,  and  losing  itself  at  each  side 
on  the  rami  of  the  ischia. 

The  inter-articular  fibro-cartilage,  seen  on  opening  the 
symphysis,  is  composed  of  concentric  Ia3rers  of  fibres  firmly 
attached  to  the  opposed  surfaces  of  the  bones,  and  project- 
ing a  little  beyond  their  borders.  At  the  posterior  part,  a 
cavity,  containing  a  fluid  like  the  synovial,  and  of  variable 
size,  will  be  found  separating  the  cartilage  into  two  lateral 
halves  ;  this  cavity  is  said  to  increase  in  size  during  preg- 
nancy. 

The  obturator  ligament,  or  membrane,  is  a  tendino-fibrous 
expansion,  which  stretches  across  the  obturator  foramen, 
and  closes  it  in  its  entire  extent,  except  at  the  upper  part, 
where  the  obturator  artery  and  nerve  pass  out  of  the  pelvis. 


The  COXO-FEMORAL  ARTICULATION,  or  HIP-JOINT,  in 
which  the  head  of  the  femur  is  received  into  the  cot}"loid 
cavity  of  the  os  innominatum,  is  maintained  by  a  capsular 
and  an  inter-articular  ligament. 

The  capsular  ligament  extends  from  the  circumference  of 
the  acetabulum  to  the  anterior  inter-trochanteric  line  of  the 
femur  in  front  and  to  the  neck  of  the  bone  posteriorly.  It 
is  strengthened  anteriorly  by  a  band  of  fibres,  called  the 
ilio-femoral  ligament,  which  passes  from  the  anterior  infe- 
rior spinous  process  of  the  ilium  to  the  inter-trochanteric 
line.  The  anterior  portion  of  the  capsular  ligament  is  of 


LIGAMENTS    OF    THE    KNEE-JOINT.  251 

great  strength,  and  that  part  of  it  arising  from  the  anterior 
inferior  spinous  process  of  the  ilium  and  inserted  into  the 
inter-trochanteric  line,  including  what  is  known  as  the  ilio- 
femoral  ligament,  divides  inferiorly  into  two  bands,  sepa- 
rated by  an  interval,  their  disposition  resembling  an  in- 
verted letter  Y.  This  arrangement  of  the  fibres  and  its 
influence  in  maintaining,  as  well  as  causing  the  position  of 
the  head  of  the  femur,  characteristic  of  its  various  forms 
of  dislocation,  and  in  the  reduction  of  these  b3^  manipulation, 
have  been  particularly  described  by  Dr.  H.  J.  Bigelow. 

The  capsular  ligament  is  to  be  divided  transversely,  and  the  head 
of  the  femur  dislocated  from  its  socket,  to  see  the  inter-articular  liga- 
ment. Or,  better  still,  a  circular  portion  of  bone  may  be  removed  on 
the  inside  of  the  os  innominatum,  by  the  gouge,  from  the  space 
between  the  obturator  foramen  and  the  greater  sacro-ischiatic  notch, 
cutting  out  the  floor  of  the  acetabulum  ;  this  shows  the  ligament  from 
within. 

The  inter-articular  ligament,  or  ligamentum  teres^  extends 
from  the  triangular  depression  in  the  head  of  the  femur  to 
the  borders  of  the  notch  in  the  acetabulum,  where  it  blends 
with  the  fibres  of  the  transverse  ligament. 

The  cotyloid  ligament  is  a  fibro-cartilaginous  baud  at- 
tached to  the  margin  of  the  acetabulum,  the  cavity  of 
which  is  surrounded  and  deepened  by  it. 

The  transverse  ligament  is  a  band  of  fibres,  continuous 
with  those  of  the  cotyloid  ligament,  which  extends  across 
the  notch  of  the  acetabulum,  protecting  the  vessels  which 
pass  beneath  it  to  the  inter-articular  ligament  and  head  of 
the  femur. 

The  head  of  the  femur  is  not  entirely  coated  with  car- 
tilage, a  portion  of  it  around  the  depression  in  its  centre 
being  divested  of  that  covering.  In  the  cotyloid  cavity 
there  is  also  a  depression  which  has  no  cartilage  ;  this  is 
occupied  by  a  mass  of  fat,  sometimes  called  the  synodal 
gland  of  Havers. 


The  TIBIO-FEMORAL  ARTICULATION,  or  KNEE-JOINT,  is 
invested  by  a  capsule,  and  by  anterior,  posterior,  external 
and  internal,  lateral  ligaments. 

The  capsule  is  a  fibrous  membrane  which  surrounds  the 
heads  of  the  bones,  and  fills  the  intervals  of  the  stronger 
special  ligaments.  It  is  connected  with  the  patella,  femur, 


252   ANATOMY  OF  THE  LOWER  EXTREMITY 

tibia  and  the  inter-articular  cartilages,  and  is  lined  inter- 
nally by  the  synovial  membrane. 

The  external  lateral  ligament  is  a  rounded  bundle  of 
fibres,  extending  between  the  external  condyle  and  the  head 
of  the  fibula ;  a  second  bundle  is  sometimes  found  posterior 
to  this,  and  called  the  short  external  lateral  ligament. 

The  internal  lateral  ligament  is  attached  to  the  internal 
condyle  above,  and  the  inner  tuberosity  of  the  tibia  below  ; 
its  limits  are  not  distinctly  marked ;  the  inferior  internal 
articular  artery,  and  the  tendon  of  the  semi-membraiiosus, 
pass  beneath  it. 

The  anterior  ligament,  or  ligamentum  patellse,  is  attached 
to  the  lower  border  of  the  patella  above,  and  the  tubercle 
of  the  tibia  below ;  a  bursa  will  be  found  beneath  its  in- 
sertion into  the  tubercle. 

The  posterior  ligament,  or  ligamentum  posticum  Wins- 
lowii,  is  formed  chiefly  by  fibres  of  the  tendon  of  the  semi- 
membranosus  muscles,  which  pass  across  the  joint  to  the 
outer  condyle ;  a  deeper  set  of  fibres  is  continuous  with  the 
general  capsule. 

The  knee-joint  is  to  be  opened  by  an  incision  along  each  side  and 
across  the  front,  above  the  patella  ;  the  patella  and  its  ligament  are 
to  be  turned  downward ;  this  exposes  the  synovial  membrane  and 
inter-articular  ligaments. 

The  synovial  membrane,  coextensive  with  the  capsule, 
covers  the  cartilages  of  the  bones,  and  all  the  inter-articu- 
lar structures  ;  it  forms  a  pouch  on  each  side  of  the  patella, 
extending  above  and  below  it  a  distance  sometimes  as 
great  as  two  inches ;  posteriorly  it  sends  a  pouch  between 
the  head  of  the  popliteus  muscle  and  the  tibia.  A  fold  of 
the  synovial  membrane,  called  the  mucous  ligament,  ex- 
tends from  between  the  condyles  to  the  fat  below  the 
patella ;  this  is  continued  outward  to  the  sides  of  the 
patella,  under  the  name  of  the  alar  ligaments. 

The  crucial  ligaments  are  two  strong  bands,  the  anterior 
of  which,  arising  from  the  depression  in  front  of  the  spine 
of  the  tibia,  goes  to  the  inner  surface  of  the  external  con- 
dyle, and  the  posterior  from  the  depression  behind  the 
spine  to  the  inner  surface  of  the  internal  condyle  ;  the  in- 
ternal ligament  is  larger  than  the  external.  The  respective 
insertions  of  the  crucial  ligaments  are  difficult  to  remem- 
ber; the  initial  letters  of  the  words,  anterior  external, 


LIGAMENTS    OF    THE    ANKLE.  253 

posterior  internal,  manufacture  the  word  AEPI,  from  which 
the  memory  may  derive  assistance. 

The  semi-lunar  fibro-cartilages  are  two  crescentic  plates 
of  cartilage  placed  upon  the  margins  of  the  head  of  the 
tibia,  and  attached  externally  to  the  capsule  of  the  joint ; 
they  are  thick  along  their  convex  borders  and  thin  at  their 
concave,  being  hollowed  out  to  receive  the  condyles  of  the 
femur;  they  are  connected  anteriorly  with  the  front  of  the 
tibia,  and  posteriorly  with  its  spine.  The  internal  cartilage 
forms  the  segment  of  a  larger  circle  than  the  external,  and 
is  more  ovoidal  in  shape. 

The  transverse  ligament  unites  these  cartilages  anteri- 
orly ;  sometimes  it  hardly  exists. 

The  tibia  and  fibula  are  articulated  together  at  their  two 
extremities,  and  connected  between  their  shafts  by  an  inter- 
osseous  membrane. 

The  union  between  the  bones  superiorly  is  effected  by 
anterior  and  posterior  bands  from  the  tuberosity  of  the, 
tibia  to  the  head  of  the  fibula.  Inferior!  y,  an  anterior  band 
crosses  in  front  from  the  fibula  to  the  tibia,  and  a  posterior 
one  is  similarly  disposed  behind  the  ankle-joint;  an  inferior 
interosseous  ligament  closes  the  space  between  the  ends  of 
the  two  bones  below,  and  may  be  seen  by  forcibly  tearing 
them  apart. 

The  interosseous  membrane  is  attached  to  the  contiguous 
sides  of  the  shafts  of  the  tibia  and  fibula,  and  separates 
the  muscles  of  the  back  from  those  of  the  front  of  the  leg ; 
its  fibres  are  directed  downward  and  outward,  and  are 
crossed  by  a  few  passing  in  the  opposite  direction ;  they 
are  deficient  above,  at  the  point  where  the  anterior  tibial 
artery  enters,  and  below,  where  the  anterior  peroneal  artery 
comes  forward  from  the  back  of  the  leg,  to  be  distributed 
upon  the  tarsus. 


The  TIBTO-TARSAL  ARTICULATION,  or  ANKLE-JOINT,  is 
formed  by  the  fibula,  the  tibia,  and  the  astragalus,  and  is 
maintained  by  four  ligaments,  anterior,  posterior,  external, 
and  internal. 

The  anterior  ligament  is  a  thin  membranous  layer,  ex- 
tending from  the  front  of  the  tibia  to  the  upper  part  of 
the  astragalus,  and  continuous  by  its  sides  with  the  lateral 
ligaments. 

The  internal  lateral,  or  deltoid  ligament,  expands,  fan- 
22 


254   ANATOMY  OP  THE  LOWER  EXTREMITY. 

shaped,  from  the  tip  of  the  malleolus,  to  be  inserted  into  the 
inner  side  of  the  astragalus,  os  calcis,  and  scaphoid  bone. 
The  ligament  is  covered  in  by  the  internal  annular  ligament 
(p.  244),  and  the  tendons  which  pass  through  it. 

The  external  lateral  ligament  consists  of  three  strong 
fasciculi;  the  anterior  of  which  passes  from  the  anterior 
border  of  the  malleolus  to  the  surface  of  the  astragalus 
in  front  of  it ;  the  middle  descends  from  the  tip  of  the  mal- 
leolus to  the  side  of  the  os  calcis,  and  the  posterior  from 
the  posterior  border  of  the  malleolus,  horizontally  back- 
ward, to  the  posterior  surface  of  the  astragalus. 

The  tarsal  bones  of  the  foot  are  united  by  dorsal,  plantar, 
and  interosseous  ligaments. 

The  dorsal  ligaments  unite  each  tarsal  bone  with  those 
contiguous  to  it ;  several  strong  bands  pass  forward  from 
the  deep  fossa  between  the  astragalus  and  os  calcis,  to  the 
scaphoid  and  cuboid  bones,  under  the  name  of  calcaneo- 
cuboid  and  astragalo-scaphoid  ligaments. 

The  plantar  ligaments  also  consist  of  short  bands  uniting 
the  contiguous  bones,  with  the  addition,  however,  of  two 
others  of  large  size  and  great  strength.  The  inferior  cal- 
caneo-scaphoid  ligament  unites  the  os  calcis  and  the  scaphoid 
bone,  forming  part  of  the  cavity  which  receives  the  rounded 
head  of  the  astragalus;  the  tendon  of  the  tibialis  posticus 
crosses  this  ligament.  The  long  calcaneo-cuboid  ligament 
passes  from  the  under  surface  of  the  os  calcis  to  the  rough 
ridge  on  the  under  part  of  the  cuboid  bone;  some  of  its 
fibres  continue  over  the  tendon  of  the  peroneus  longus, 
forming  a  sheath  for  it,  and  are  inserted  into  the  bases  of 
the  third  and  fourth  metatarsal  bones;  these  last-named 
fibres  are  sometimes  called  the  ligamentum  longum  plantse, 
and  the  shorter  ones  the  ligamentum  breve  plantse. 

The  interosseous  ligaments  are  five  in  number,  and  are 
strong  bands  intervening  between  the  contiguous  surfaces 
of  the  adjoining  tarsal  bones.  The  caloaneo-astragaloid  lies 
in  the  fossa  between  the  os  calcis  and  astragalus,  and  can 
only  be  seen  by  a  longitudinal  section  of  the  two  bones, 
when  it  will  be  found  as  a  short,  stout  band,  attached  to  a 
depression  in  each  bone.  Another  interosseous  ligament 
exists  between  the  articulating  surfaces  of  the  cuboid  and 
scaphoid  bones,  and  three  others  between  the  three  cunei- 
form and  the  cuboid  bones. 

The  bases  of  the  metatarsal  bones  are  united  by  dorsal, 
plantar,  and  interosseous  ligaments ;  the  interosseous  liga- 


LIGAMENTS    OF    THE    FOOT.  255 

ments  are  to  be  demonstrated  by  tearing  the  bones  apart, 
when  the  dissection  is  completed.  These  ligaments  are 
only  found  between  the  outer  four  metatarsal  bones,  that 
of  the  great  toe  not  being  united  with  the  others;  the  second 
and  third  metatarsal  bones  are  also  firmly  connected  with 
the  external  and  internal  cuneiform  bones.  The  heads  of 
the  metatarsal  bones  are  connected  inferiorly  by  transverse 
metatarsal  ligaments. 

The  metatarso-plialangeal  articulations  are  maintained 
by  two  lateral  ligaments  and-  an  inferior  ligament,  the 
expansion  of  the  extensor  tendon  supplying  the  place  of  a 
superior  one. 

The  phalanges  are  united  to  each  other  by  two  lateral 
ligaments  and  an  inferior  ligament,  and  by  the  expansion 
of  the  extensor  tendon  superiorly.  The  joints  between  the 
phalanges  are  sometimes  very  indistinct,  and  occasionally 
co-ossified.  The  ligamentous  arrangements  and  the  inser- 
tions of  the  tendons  are  precisely  the  same  as  in  the  fingers, 
and  are  much  more  satisfactorily  studied  in  the  hand,  the 
description  of  which  is  given  at  p.  160. 


PECULIARITIES 


IN    THE 


ANATOMY   OF   THE   FO3TUS. 


Upon  the  foetus  may  be  demonstrated  almost  all  the  anatomy  of  the 
adult  human  system  ;  the  points  in  which  it  differs  from  that  of  adults 
will  alone  be  noticed. 

The  full-grown  fetus  weighs  about  seven  pounds,  and  is 
seventeen  inches  in  length,  or  thereabout ;  the  umbilicus  is 
situated  from  a  quarter  to  half  an  inch  below  the  middle  of 
the  body.  The  external  genital  organs  are  largely  developed, 
especially  the  labia  minora  in  the  female,  which  project  be- 
yond the  labia  majora ;  in  the  male,  the  prepuce  is  adherent 
to  the  glans  penis,  constituting  a  state  of  phymosis.  The 
muscles  are  pale,  and  of  a  softer  texture  than  when  more 
developed,  and  are  covered  in  with  a  dry  and  granular  fat, 
easily  detached  from  them. 

The  umbilical  cord  is  composed  of  two  umbilical  arteries, 
and  an  umbilical  vein,  imbedded  in  a  soft,  semi-transparent 
substance,  called  the  Whartonian  gelatine.  Within  the  ab- 
domen, the  arteries  are  called  the  hypogastric. 

The  abdomen  is  to  be  opened  in  such  a  way  as  to  avoid  injuring  the 
vessels  which  diverge  upward  and  downward  from  the  umbilicus. 

The  HYPOGASTRIC  ARTERY  is  the  internal  iliac  artery  of 
adult  life ;  it  is  larger  than  the  external  iliac,  and  may  be 
traced  from  the  common  iliac  artery  upward,  along  the 
side  of  the  urinary  bladder  and  urachus,  to  the  anterior 
wall  of  the  abdomen,  upon  which  it  ascends  to  the  umbili- 
cus, where  the  two  arteries  come  together,  escape  from  the 
abdomen  with  the  umbilical  vein,  and  coil  around  it  in  the 
umbilical  cord,  until  they  reach  the  placenta.  After  the 
cessation  of  the  placental  circulation,  this  artery  becomes 
impervious  from  the  side  of  the  bladder  upward,  and  is 


ANATOMY    OP    THE    FCETUS.  257 

converted  into  a  fibrous  cord  (p.  208) ;  an  inch  or  so  of  its 
commencement  always  remains  pervious,  and  gives  origin 
to  the  superior  vesical  artery. 

The  UMBILICAL  VEIN  runs  from  the  umbilicus  along  the 
free  margin  of  the  suspensory  ligament  of  the  liver  to  the 
transverse  fissure  of  that  organ  ;  it  there  divides  into  three 
branches,  one  of  which  is  distributed  to  the  left  lobe,  one 
to  the  right  lobe,  larger  than  the  preceding,  and  which  is 
joined  by  the  vena  portae,  and  a  third  branch,  smaller  than 
either  of  the  others,  the  ductus  venosus,  which  terminates 
in  the  left  hepatic  vein.  After  the  cessation  of  the  placental 
circulation,  the  umbilical  vein  and  ductus  venosus  become 
converted  into  a  fibrous  cord,  the  former  becoming  the 
round  ligament  of  the  liver. 

The  LIVER  occupies  the  whole  upper  part  of  the  abdo- 
men ;  it  is  of  a  dark,  mahogany  color,  and  its  lobes  are 
nearly  equal  in  size.  After  birth,  it  rapidly  diminishes  in 
bulk ;  and,  at  the  age  of  five  or  six  years,  attains  the  pro- 
portions maintained  during  the  rest  of  life. 

The  KIDNEYS  present  a.  tabulated  appearance,  and  are 
relatively  larger  than  in  the  adult.  The  supra-renal  cap- 
sules are  also  of  large  size. 

The  BLADDER  is  long  and  conical,  and  is  connected  supe- 
riorly with  the  umbilicus  by  a  fibrous  cord  called  the 
urachus.  This  is  an  obliterated  tube  which  during  the 
early  part  of  intra-uterine  life  connected  the  bladder  with 
one  of  the  foetal  membranes  called  the  allantois. 

The  INTESTINES  are  small  in  calibre,  and  contain  a  dark 
green  substance  called  meconium.  The  small  intestines 
are  devoid  of  valvulae  conniventes,  or  these  are  but  imper- 
fectly developed.  The  appendix  of  the  caecum  is  long  and 
of  large  size,  and  seems  like  a  tapering  continuation  of  the 
caecum  itself. 

The  TESTES,  in  the  early  part  of  foetal  life,  are  situated 
in  the  lumbar  region,  behind  the  peritoneum.  About  the 
fifth  month  they  begin  to  descend  to  the  scrotum,  but  not 
unfrequently  they  may  be  found  delayed  in  some  part  of 
their  course  at  the  time  of  birth.  Connected  with  the  lower 
end  of  the  testicle  and  epididymis  is  a  band  composed  of 
areolar  and  muscular  tissue,  called  the  gubernaculum  teslis, 
which  guides  and  assists  their  gradual  descent;  it  extends 
through  the  ing'  nal  canal,  and  is  attached  to  the  front 
of  the  pubes  and  the  bottom  of  the  scrotum.  When  the 
testicle  is  about  to  enter  the  internal  abdominal  ring,  a 

22* 


258  ANATOMY    OF    THE    PCETUS. 

small  pouch  of  peritoneum  will  be  found  protruding  at 
that  point,  and  into  this  the  testicle  projects  from  behind, 
supported  by  a  duplicature,  or  suspensory  fold,  of  the  peri- 
toneum, called  the  mesorchium ;  this  pouch,  under  the 
name  of  processus  vaginalis  peritonei,  precedes  the  testicle 
in  its  course  through  the  inguinal  canal,  and  enters  the 
scrotum  in  advance  of  the  gland.  The  neck  of  this  pouch, 
by  which  it  is  connected  with  the  general  peritoneal  cavity, 
becomes  gradually  obliterated  after  birth,  while  the  pouch 
itself  remains  as  an  independent  serous  sac,  under  the 
name  of  tunica  vaginalis  testis. 

The  ovaries  in  the  female  are  likewise  placed  in  the  lum- 
bar region,  and  gradually  descend  to  the  pelvis.  A  pouch 
of  peritoneum,  analogous  to  the  processus  vaginalis  of  the 
male,  accompanies  the  round  ligament  of  the  uterus  for 
a  short  distance  into  the  inguinal  canal,  and  is  called  the 
canal  of  Nuck. 

On  opening  the  thorax  there  is  found  in  the  anterior 
mediastinum,  and  extending  upward  upon  the  trachea  into 
the  neck,  a  narrow,  elongated^  body,  lobulated,  pinkish  in 
color,  and  soft  in  texture ;  this  is  the  THYMUS  GLAND.  It 
consists  of  two  lateral  lobes  enveloped  in  an  areolar  cap- 
sule. A  central  cavity,  containing  a  milky  fluid,  exists  in 
each  lobe;  it  has  no  duct  or  outlet.  The  thymus  gland 
increases  in  size  for  about  two  years ;  it  then  dwindles, 
and  becoming  converted  into  a  fatty  mass,  at  the  age  of 
puberty  has  nearly  disappeared. 

The  LUNGS  are  small,  and  lie  packed  in  the  posterior 
part  of  the  thorax.  Previous  to  respiration  they  consist 
of  a  dense,  gland-like  substance.  Subsequently  to  respira- 
tion they  are  of  a  pinkish,  spongy  structure,  expanding 
and  completely  filling  the  pleural  cavity. 

The  HEART  is  well  developed  in  point  of  size,  but  the 
septum  between  the  auricles  is  incomplete,  being  perforated 
by  a  large  opening  called  the  foramen  ovale.  A  communi- 
cation will  also  be  found  between  the  left  pulmonary  artery 
and  the  aorta,  just  beyond  the  origin  of  the  brachio-cephalic 
vessels,  by  a  short  trunk  called  the  ductus  arteriosus ;  this 
degenerates  into  a  fibrous  cord  shortly  after  birth,  and  the 
foramen  ovale  usually  becomes  obliterated.  The  Eus- 
tachian  valve  is  of  large  size,  and  seems  to  be  a  continua- 
tion upward  of  the  anterior  wall  of  thmcnferior  vena  cava 
toward  the  foramen  ovale. 

The   FCETAL   CIRCULATION  presents   peculiarities.     The 


ANATOMY    OF    THE    F(ETUS.  259 

oxygenized  blood  from  the  placenta  is  brought  by  the  um- 
bilical vein  to  the  inferior  vena  cava,  where  it  of  course 
mixes  with  the  impure  blood  from  the  lower  extremities ; 
entering  the  right  auricle,  its  current  is  directed  by  the 
large  Eustachian  valve  toward  the  foramen  ovale,  through 
which  it  passes  into  the  left  auricle.  The  blood  from  the 
head  and  upper  extremities,  which  is  returned  by  the  supe- 
rior vena  cava  as  venous  blood,  enters  the  right  auricle,  and 
passes  by  the  auriculo-ventricular  opening  into  the  right 
ventricle ;  the  crossing  of  these  two  currents  in  the  right 
auricle  is  permitted  by  the  construction  of  the  Eustachian 
valve,  though,  to  a  certain  extent,  the  two  streams  must 
intermingle. 

We  thus  see  that  the  blood  brought  to  the  right  auricle 
has  two  sources  of  exit,  viz :  the  foramen  ovale  and  the 
auricnlo-ventricular  orifice.  By  following  the  blood  from 
the  cavities  into  which  these  orifices  open,  as  if  it  had 
started  originally  from  these  points,  we  shall  at  once  com- 
prehend the  foetal  circulation.  Thus,  that  from  the  right 
ventricle  must  enter  the  pulmonary  artery  which  goes  to 
the  lungs;  but  the  lungs  are  solid  and  impervious,  and 
nature  has  therefore  provided  an  exit  for  it  by  the  ductus 
arteriosus,  through  which  it  reaches  the  aorta  at  a  point 
bej^ond  the  origin  of  the  brachio-cephalic  branches,  and 
is  carried  to  the  body  and  lower  extremities.  Then,  again, 
the  blood  which  is  in  the  left  auricle  can  go  only  to  the  left 
ventricle,  and  from  there  it  must  go  to  the  aorta.  This 
portion  of  the  blood  being  that  from  the  placenta,  and 
therefore  the  most  richly  oxygenized,  is  able  to  enter  the 
brachio-cephalic  trunks,  which  the  other  current  could  not 
do,  and  supplies  the  important  parts  to  which  they  are 
distributed.  Beyond  the  origin  of  the  brachio-cephalic 
trunks  that  portion  of  the  blood  which  has  not  entered 
those  vessels,  joins  with  the  current  from  the  ductus  arte- 
riosus, helps  to  supply  the  body  and  lower  extremities,  and 
is  returned  to  the  placenta  by  the  hypogastric  arteries. 


IMPORTANT  ANATOMICAL  LANDMARKS  AND  POINTS, 


CAPABLE  OF  BEING  STUDIED  WITHOUT  DISSECTION,  OR  UPON 
THE  LIVING  SUBJECT. 


CRANIUM. 

THE  position  of  the  lateral  sinus  is  indicated  by  a,  line 
nearly  horizontal,  drawn  from  the  occipital  protuberance, 
which  may  be  felt  at  the  back  of  the  head,  to  the  base  of 
the  mastoid  process  of  the  temporal  bone. 

The  position  of  the  longitudinal  sinus  is  indicated  by 
a  line  drawn,  over  the  vertex,  from  the  root  of  the  nose  to 
the  occipital  protuberance. 

The  middle  meningeal  artery  follows  a  course  upward 
from  the  anterior  inferior  angle  of  the  parietal  bone,  or 
from  a  point  about  one  and  a  half  inches  behind  the  ex- 
ternal angular  process  of  the  frontal  bone. 

It  is  not  usual  to  apply  the  trephine  over  the  region 
traversed  by  the  lower  part  of  the  meningeal  artery,  or 
over  those  corresponding  to  either  of  the  above  named 
sinuses. 

FACE. 

The  supra-orbital  foramen,  from  which  issues  the  supra- 
orbital  branch  of  the  fifth  nerve,  is  situated  a  little  inside 
of  the  union  of  the  inner  with  the  outer  two-thirds  of  the 
upper  margin  of  the  orbit.  Its  position  may  also  be  de- 
termined by  the  pulsations  of  the  supra-orbital  branch  of 
the 'ophthalmic  artery,  issuing  from  it,  and  which,  though 
the  vessel  is  of  small  size,  may  still  be  detected. 

The  infra-orbital  foramen,  from  which  issues  the  infra- 
orbital  branch  of  the  fifth  nerve,  is  situated  just  above  the 
canine  fossa,  one-fourth  of  an  inch  below  the  lower  edge  of 
the  orbit.  A  vertical  line  dropped  from  this  foramen  would 
fall  upon  the  first  molar  tooth. 


FACE.  261 

The  lachrymal  can als,  superior  and  inferior,  arc  situated 
at  the  inner  angle  of  the  eyelids,  in  their  free  margin.  Their 
orifices,  or  puncta,  present  slight  prominences,  are  directed 
inward  towards  the  globe  of  the  eye,  and  it  is  necessary 
that  the  lid  should  be  slightly  everted  to  see  them.  The 
canals  are  at  first  directed  vertically,  the  superior  from 
below  upward,  and  the  inferior  from  above  downward;  they 
then  speedily  bend  at  a  right  angle  and  continue  inward  to 
the  lachrymal  sac,  which  they  usually  enter  by  separate 
orifices.  The  length  of  the  canals  is  three  or  four  lines, 
and  the  lower  is  a  little  shorter  and  larger  than  the  upper. 
In  introducing  a  probe  the  lid  should  be  drawn  outward, 
so  as  to  obliterate  the  angle  of  the  canal  and  convert  it 
more  nearly  into  a  straight  tube. 

The  lachrymal  sac  occupies  a  position  at  right  angles  to 
the  lachrymal  canals.  It  is  crossed  at  its  middle  by  the 
tendo  oculi,  and  this  tendon  may  be  made  apparent  to  the 
touch  by  drawing  the  lids  outward.  A  knife  entering  below 
this  tendon,  and  just  within  the  edge  of  the  orbit,  would 
penetrate  the  sac.  A  probe  introduced  at  this  puncture, 
and  passing  downward,  backward,  and  outward,  would 
traverse  the  nasal  duct,  and  appear  in  the  inferior  meatus 
of  the  nasal  fossa. 

The  orifice  of  the  nasal  duct  is  to  be  found  in  the  roof  of 
the  inferior  meatus  of  the  nasal  fossa,  beneath  the  inferior 
turbinated  bone,  about  three  quarters  of  an  inch  from  the 
ala  nasi,  or,  it  is  said, "  at  a  distance  equal  to  that  between 
the  inner  angles  of  the  eyelids."  This  duct  may  be  explored 
from  its  nasal  orifice  by  means  of  Gensoul's  probe. 

The  Eustachian  tube  may  be  explored  by  a  probe  with  a 
very  short  curve,  carried  along  the  inferior  meatus  of  the 
nasal  fossa,  until  it  reaches  beyond  the  hard  palate ;  then 
turning  the  probe  outward,  it  will  enter  the  orifice,  by 
which  this  tube  opens  into  the  pharynx  behind  the  inferior 
turbinated  bone.  The  finger  passed  into  the  mouth,  and 
turned  up  behind  the  velum  pendulum  palati,  will  detect, 
upon  the  outer  and  upper  wall  of  the  pharynx,  the  cartila- 
ginous lips,  covered  with  mucous  membrane,  which  charac- 
terize its  opening. 

The  parotid,  or  Steno's  duct,  follows  a  course  indicated 
by  a  line  drawn  from  the  tip  of  the  lobe  of  the  ear,  for- 
ward, and  nearly  horizontally.  This  line  crosses  the  mas- 
seter  muscle,  at  the  border  of  which  the  duct  turns  inward, 
to  open  in  the  mouth  by  an  orifice  in  the  cheek,  opposite 


262       IMPORTANT    ANATOMICAL    LANDMARKS. 

the  first  or  second  molar  tooth.  It  passes  in  close  proximity 
to  the  lower  border  of  the  inalar  bone.  The  transverse 
facial  artery  lies  just  above  the  duct,  and  an  important 
branch  of  the  facial  nerve,  which  supplies  the  buccinator 
muscle,  accompanies  it  along  its  upper  edge. 

The  antrum  of  the  superior  maxilla  ma}^  easily  be  reached 
by  perforating  the  bone  at  the  fossa  on  its  anterior  surface, 
just  over  the  second  bicuspid  tooth,  or,  through  the  alveolar 
cavity  from  which  a  molar  tooth  has  been  extracted. 

The  facial  artery  crosses  the  lower  jaw  obliquely  towards 
the  angle  of  the  lips,  in  front  of  the  insertion  of  the  mas- 
seter  muscle,  the  outline  of  which  is  distinguishable  in  most 
subjects.  In  front  of  the  angle  of  the  inferior  maxilla,  the 
finger  will  detect  a  superficial  notch,  in  which,  with  rare 
exceptions,  the  facial  artery  lies,  and  where  its  pulsations 
may  be  felt. 

The  mental  foramen,  from  which  issues  the  inferior  den- 
tal branch  of  the  fifth  nerve,  is  situated  a  little  nearer  to  the 
alveolar  than  the  lower  border  of  the  inferior  maxilla,  at  a 
point  corresponding  to  the  canine  tooth,  or  to  the  interval 
between  it  and  the  bicuspid  tooth.  The  supra  and  infra- 
orbital  and  mental  foramina,  are  not  always  in  a  vertical 
line,  one  with  the  other,  as  is  sometimes  asserted. 

To  explore  the  throat,  the  tongue  should  be  slightly  pro- 
truded ;  the  mouth  being  widely  open,  the  posterior  fauces 
and  pharynx  will  be  displayed  by  inspiring,  and  repeatedly 
pronouncing  the  syllable  "  hah." 

The  glands  of  the  tongue  may  be  advantageously  studied 
upon  the  living  subject. 

The  ranine  arteries  are  situated  at  the  bottom  of  the 
frenum  linguae,  where  it  blends  with  the  floor  of  the  mouth. 
The  large  size  of  the  ranine  veins,  lying  upon  the  under 
surface  of  the  tongue,  should  be  noticed.  On  each  side  of 
the  lower  border  of  the  frenum,  the  Ewinian  and  Whartonian 
ducts  open.  Their  orifices  in  the  centre  of  an  obvious 
papilla  may  be  plainly  seen. 

The  tonsil  is  situated  between  the  anterior  and  posterior 
pillars  of  the  fauces.  In  its  natural  and  healthy  condition 
it  hardly  projects  be}7ond  these.  The  internal  carotid 
artery  lies  at  its  base,  and  is  separated  from  it  by  an  inter- 
vening aponeurosis  and  by  the  constrictor  muscle  of  the 
pharynx.  This  interval  is,  however,  of  considerable  thick- 
ness. The  angle  of  the  inferior  maxillary  bone  corresponds 
externally  in  its  situation  to  that  of  the  tonsil  internally. 


NECK.  2G3 

The  epiglottis  may  be  seen  by  depressing  the  tongue  with 
a  spatula. 

The  student  should  practice  himself  upon  the  dead  sub- 
ject in  the  extraction  of  teeth. 

NECK. 

The  external  jugular  vein  follows  a  course  indicated  by 
a  line  drawn  from  the  angle  of  the  lower  jaw  to  the  middle 
of  the  clavicle. 

The  common  carotid  artery,  in  the  male,  bifurcates  at  a 
point  on  a  level  with  the  upper  border  of  the  thyroid  car- 
tilage ;  in  the  female,  opposite  the  middle  of  this  cartilage. 

The  anterior  border  of  the  sterno-mastoid  muscle  covers 
the  common,  as  well  as  the  external  and  internal  carotid 
arteries,  the  direction  of  which  is  indicated  by  a  line  drawn 
from  midway  between  the  anterior  border  of  the  mastoid 
process  of  the  temporal  bone  and  the  ascending  ramus  of 
the  lower  jaw,  to  a  point  half  an  inch  outside  of  the  sterno- 
clavicular  articulation.  The  common  carotid  is  more  deeply 
situated  at  the  base  of  the  neck  than  higher  up,  and  its 
position  in  this  part  of  its  course  corresponds  to  the  in- 
terval between  the  sternal  and  clavicular  attachments  of 
the  sterno-mastoid  muscle.  The  artery  may  be  compressed 
against  the  transverse  processes  of  the  cervical  vertebrae. 
The  posterior  border  of  the  sterno-mastoid  muscle  corre- 
sponds to  the  posterior  border  of  the  scalenus  anticus  mus- 
cle, which  lies  beneath  it,  and  is,  in  part,  the  guide  to  the 
subclavian  artery. 

In  the  adult  subject  the  rings  of  the  trachea  commence 
one  and  a  half  inches  above  the  sternum;  by  throwing 
back  the  head  an  additional  half  inch  may  be  exposed. 
The  upper  three  rings  are  covered  by  the  isthmus  of  the 
thyroid  body.  The  trachea  grows  deeper  as  it  descends, 
and  at  the  base  of  the  neck  is  sometimes  an  inch  and  a  half 
from  the  surface.  The  cricoid  cartilage  can  always  be  felt 
even  in  infants ;  it  corresponds  to  the  fifth  cervical  verte- 
bra. The  commencement  of  the  oesophagus  is  immediately 
behind  this  cartilage. 

The  pulsations  of  the  subclavian  artery  may  be  felt, 
deeply,  behind  the  clavicle,  in  the  interval  between  the 
posterior  border  of  the  sterno-mastoid  and  the  anterior 
border  of  the  trapezius  muscles.  By  pressure  downward 
and  backward,  the  artery  may  be  compressed  against  the 


264       IMPORTANT     ANATOMICAL    LANDMARKS. 

first  rib,  which  it  crosses.  The  interval  between  the  above- 
named  muscles  may  be  obliterated  by  their  great  degree  of 
development. 

The  not  unfrequent  extension  of  the  pleural  cavity  above 
the  clavicle,  sometimes  to  an  extent  of  two  and  even  three 
inches,  will  be  made  apparent  on  inflating  the  apex  of  the 
lung  by  a  full  and  forced  inspiration,  and  by  percussion. 

CHEST. 

The  arteria  innominata  corresponds  in  position  to  a  line 
drawn  from  the  centre  of  the  union  of  the  first  with  the 
second  bone  of  the  sternum,  to  the  right  sterno-clavicular 
articulation ;  by  extending  the  neck  its  pulsations  may  be 
felt. 

The  nipple,  in  the  male,  lies  upon  the  space  between  the 
fourth  and  fifth  ribs. 

The  coracoid  process  of  the  scapula  may  be  felt  below 
the  clavicle,  in  the  interspace  between  the  deltoid  and  pec- 
toralis  major  muscles.  The  line  of  this  interspace  corre- 
sponds to  that  of  the  course  of  the  axillary  artery. 

The  position  of  the  heart  may  be  determined  by  percus- 
sion. "  The  apex  pulsates  between  the  fifth  and  sixth  ribs, 
two  inches  below  the  nipple  and  one  inch  to  its  sternal  side. 
The  aortic  valves  lie  behind  the  third  intercostal  space  to 
the  left  of  the  sternum.  The  pulmonary  valves  lie  behind 
the  junction  of  the  third  rib,  on  the  left  side,  with  the 
sternum.  The  tricuspid  valves  lie  behind  the  middle  of 
the  sternum,  about  the  level  of  the  fourth  costal  cartilage. 
The  mitral  valves  lie  behind  the  third  intercostal  space, 
about  one  inch  to  the  left  of  the  sternum." 

The  bifurcation  of  the  trachea  corresponds  in  position 
to  the  line  of  union  between  the  first  and  second  bones  of 
the  sternum. 

The  lower  margin  of  the  lung,  anteriorly,  corresponds  to 
the  most  depending  portion  of  the  sixth  rib ;  laterally,  to 
the  eighth  rib ;  posteriorly,  to  the  tenth  rib.  It  is  obvious, 
therefore,  that  the  pleural  cavity  may  be  penetrated  with- 
out the  lung  being  wounded. 

BACK. 

The  scapula  covers  the  ribs  from  the  seventh  to  the 
tenth,  inclusive. 

The  bifurcation  of  the  trachea  corresponds  in  position 
to  the  spine  of  the  third  dorsal  vertebra. 


BACK — ABDOMEN.  2fi5 

The  kidney  lies  in  front  of  the  last  two  or  three  ribs, 
and  sometimes  its  lower  extremity  does  not  reach  below 
the  twelfth  rib.  Its  position  is  outside  the  erector  spinae 
muscle. 

The  cauda  equina  commences  at  the  second  lumbar  ver- 
tebra. 

The  descending  colon  may  be  opened  without  wounding 
the  peritoneum,  in  an  operation  called  colotomy,  by  a  trans- 
verse incision,  upon  the  left  side,  two  fingers'  breadth  above 
the  crest  of  the  ilium,  outside  the  erector  spinse  muscle. 

The  prominences  of  the  posterior  superior  spinous  pro- 
cesses of  the  ilium  should  be  noticed.  Pressure  during  pro- 
tracted confinement  to  the  back  in  bed,  frequently  causes 
the  integument  over  them  to  slough,  and  gives  rise  to  "bed- 
sores." 

The  gluteal  artery  emerges  from  the  greater  sacro-ischi- 
atic  foramen  at  a  point  which  corresponds  to  the  middle  of 
a  line,  drawn  from  the  posterior  superior  spinous  process 
of  the  ilium  to  the  upper  border  of  the  trochanter  major. 

ABDOMEN. 

tThe  xiphoid  cartilage  of  the  sternum  corresponds  in 
position  to  the  tenth  dorsal  vertebra.  Its  variations  in 
shape  and  direction,  in  different  subjects,  should  be  ob- 
served. 

The  pulsations  of  the  aorta  may  readily  be  felt,  in  an 
emaciated  person,  through  the  abdominal  parietes.  It  may 
be  compressed  against  the  vertebral  column.  The  bifur- 
cation of  the  aorta  corresponds  to  a  point  just  below,  and 
a  little  to  the  left  of,  the  umbilicus,  and  to  the  third  lumbar 
vertebra. 

The  median  line  of  the  abdomen,  which  is  sometimes 
represented  by  a  sulcus,  corresponds  to  the  linea  alba.  The 
linese  arcuatse,  along  the  outer  border  of  the  recti  mus- 
cles, may  be  made  apparent  by  throwing  these  into  a  state 
of  contraction.  The  trocar  may  be  thrust  through  either 
of  these  aponeurotic  intervals  in  the  operation  of  paracen- 
tesis  abdominis  ;  in  the  first  named,  just  below  the  umbili- 
cus ;  in  the  second,  at  a  point  midway  between  the  umbili- 
cus and  the  anterior  superior  spinous  process  of  the  ilium. 

The  epigastric  artery  pursues  a  course,  indicated  by  a 
line  drawn  from  the  middle  of  Poupart's  ligament  to  a 
point  just  above  the  umbilicus. 

The  external  abdominal  ring  may  be  explored,  and  pene- 
23 


2G6       IMPORTANT    ANATOMICAL    LANDMARKS. 


t rated  to  a  variable  degree,  by  the  forefinger,  invaginating 
the  scrotum,  and  carried  up  beneath  the  abdominal  integu- 
ment, in  a  direction  upward  and  outward,  along  the  side 
of  the  spermatic  cord,  which  serves  as  a  guide  to  the  posi- 
tion of  the  ring. 

The  regions  of  the  abdomen  are  indicated  by  arbitrary 
lines,  viz :  two  vertical  lines,  each,  from  the  most  depen- 
dent portion  of  the  cartilages  of  the  eighth  ribs  to  the 
centre  of  Poupart's  ligament;  a  transverse  line,  corre- 
sponding to  the  summits  of  the  ilia ;  a  second  transverse 
line,  corresponding  to  the  cartilages  of  the  ninth  ribs.  We 
thus  have  three  zones,  each  subdivided  into  three  regions. 
These  are  named,  in  the  upper  zone,  the  right  and  left 
hypochondriac,  and  in  the  centre,  the  epigastric;  in  the 
middle  zone,  the  right  and  left  lumbar,  and  in  the  centre, 
the  umbilical ;  in  the  lower  zone,  the  right  and  left  inguinal, 
and  in  the  centre,  the  hypogastric.  The  parts  which,  within 
the  abdomen,  correspond  to  these  regions  may  be  tabulated 
as  follows : — 


R.  Hypochondriac. 

Right  lobe  of  liver, 
and  gall-bladder ;  up- 
per part  of  ascending 
colon  ;  upper  part  of 
right  kidney  ;  right 
supra-renal  capsule. 


R.  Lumbar. 
Ascending      colon  ; 
lower    part    of    right 
kidney  ;  small   intes- 
tines. 

R.  Inguinal. 
Csecum  and  appen 
dix. 


Epigastric. 
Middle  and  pyloric 
end  of  stomach ;  left 
lobe  of  liver;  cooliac 
axis ;  semi-lunar  gan- 
glion; pancreas;  aorta; 
vena  cava  inferior. 


Umbilical. 

Transverse  colon  ; 
duodenum  ;  great  om- 
entum  ;  mesentery  ; 
small  intestines. 

Hypogastric. 
Small      intestines  ; 
bladder,  when  disten- 
ded; uterus,  in  female. 


L.   Hypochondriac. 

Cardiac  end  of  sto- 
mach;  spleen;  head 
of  pancreas;  upper  part 
of  descending  colon ; 
upper  part  of  left  kid- 
ney; left  supra-renal 
capsule. 

L.  Lumbar. 
Descending    colon  ; 
lower  part  of  left  kid- 
ney ;  small  intestines. 


L.   Inguinal. 
Sigmoid   flexure   of 
colon. 


Directly  above  the  pubes  the  bladder  may  be  reached, 
especially  when  distended,  and  may  be  punctured,  without 
fear  of  wounding  the  peritoneum,  which,  in  being  reflected 
from  the  abdominal  parietes  to  the  pelvic  viscera,  leaves 
quite  an  interval  above  the  pubic  bones. 

The  vas  defer  ens  may  be  felt  as  a  constituent  part  of 
the  spermatic  cord;  it  is  hard  and  round,  usually  situated 


UPPER    EXTREMITY.  26  Y 

near  its  posterior  surface,  and  rolls  between  the  finger  and 
thumb  searching  for  it  in  the  substance  of  the  cord. 

The  epididymis  can  be  felt  as  a  dense,  oblong  body, 
situated  at  the  upper  and  -back  part  of  the  testis  ;  its  posi- 
tion is,  however,  variable.  It  may  lie  in  apposition  with 
the  lower  border  of  the  testis,  and  constitute  what  has 
been  called  "  inversion  of  the  testis."  Its  relations  with 
the  testis  and  with  the  spermatic  cord  should  be  carefully 
appreciated. 

The  external  conformation  of  the  genital  organs  should 
be  studied ;  especially  the  variable  degree  of  development 
characterizing  the  frenum  preputii,  and  the  greater  depen- 
dence of  the  left  testicle  than  the  right,  by  which  their 
mobility  is  increased  and  their  liability  to  be  compressed, 
one  against  the  other,  by  the  thighs,  is  diminished.  The 
introduction  of  the  catheter  should  be  practised. 

In  the  female  the  vulva  is  to  be  examined,  and  the  vagi- 
nal exploration  of  the  os  uteri  practised.  The  meat  us  of 
the  female  urethra  is  situated  about  half  an  inch  below  the 
clitoris,  just  above  the  protruding  border  of  mucous  mem- 
brane forming  the  orifice  of  the  vagina.  The  lips  of  the 
meatus  offer  a  small  tubercle  to  the  touch.  The  introduc- 
tion of  the  female  catheter,  without  the  aid  of  sight,  should 
be  repeatedly  performed. 

The  prostate  may  be  felt,  as  a  rounded  and  dense  body, 
shaped  like  a  chestnut,  situated  at  the  neck  of  the  bladder, 
on  introducing  the  fore  finger,  oiled,  into  the  rectum,  as  far 
up  as  it  can  reach.  It  lies  between  the  rectum  and  the 
symphysis  pubes.  Its  dimensions  vary,  and  measurements, 
as  regards  its  size,  are  arbitrary.  In  early  life  it  is  small, 
in  old  age  it  is  hypertrophied.  Behind  this  organ,  "in  the 
median  line,  the  over-distended  bladder  may  be  punctured 
through  the  rectum. 

UPPER  EXTREMITY. 

The  greater  tuber  osity  of  the  humerus  is  on  a  line  with 
the  external  condyle  of  the  same  bone. 

The  cephalic  vein,  and  the  inferior  acromial  branch  of 
the  thoracica  acromialis  artery,  lie  in  the  depression  which 
marks  the  interval  between  the  pectoralis  major  and  del- 
toid muscles. 

The  axillary  artery  traverses  the  axilla  nearer  to  the 
anterior  than  the  posterior  border  of  that  space.  Dividing 
the  axilla,  longitudinally,  into  thirds,  the  line  of  union 


268       IMPORTANT    ANATOMICAL    LANDMARKS. 

between  the  anterior  and  middle  thirds  indicates  its  exact 
position.  Its  pulsations  may  be  felt,  and  the  artery  may 
be  compressed  against  the  head  of  the  humerus. 

The  pulsations  of  the  brachial  artery,  which  commences 
at  the  lower  border  of  the  tendon  of  the  latissimus  dorsi 
muscle,  may  be  felt  at  the  inner  edge  of  the  coraco-brachi- 
alis  and  biceps  muscles.  At  the  bend  of  the  elbow  it  occu- 
pies a  position  midway  between  the  tips  of  the  two  condyles. 
The  artery  may  be  compressed  against  the  shaft  of  the 
humerus. 

The  musculo-spiral  nerve  lies  in  the  depression  above 
the  bend  of  the  elbow,  marking  the  interval  between  the 
outer  border  of  the  brachialis  anticus  and  biceps  muscles, 
and  the  inner  border  of  the  supinator  longus  muscle. 

The  ulnar  nerve  lies  behind  the  inner  condyle  of  the 
humerus,  in  the  depression  between  it  and  the  olecranon, 
being  in  close  relation  to  the  side  of  the  latter  process. 

By  rotating  the  arm  at  the  wrist  the  head  of  the  radius 
may  be  felt  near  the  elbow,  rolling  under  the  finger  which 
searches  for  its  position.  The  forearm  should  be  flexed. 
It  then  lies  just  in  front  of  the  external  condyle. 

The  veins  at  the  bend  of  the  elbow  may  be  demonstrated 
by  the  application  of  a  ligature  tied  around  the  arm  above, 
their  consequent  distension  rendering  them  obvious  to  the 
eye  and  touch. 

The  ulnar  artery,  in  the  upper  fourth  of  its  course,  is 
indicated  by  a  line  drawn  from  the  middle  of  the  elbow 
obliquely  inward,  and  thence,  by  a  line  drawn  from  the  tip 
of  the  internal  condyle  to  the  inner  border  of  the  pisiform 
bone. 

The  radial  artery  follows  a  course  indicated  by  a  line 
drawn  from  the  middle  of  the  bend  of  the  elbow  to  the 
interval  at  the  wrist  between  the  tendons  of  the  flexor 
communis  digitorum  and  that  of  the  supinator  longus 
muscle.  The  pulsations  of  the  superficialis  volse  branch  of 
this  vessel,  when  it  is  present,  may  be  felt  upon  the  ball  of 
the  thumb,  the  muscles  of  which  it  crosses,  near  their 
origin,  in  a  direction  that  continues  the  line  of  the  radial 
artery. 

The  "anatomist's  snuff-box"  is  the  triangular  interval 
between  the  tendon  of  the  extensor  secundi  interned ii 
pollicis,  and  the  parallel  tendons  of  the  extensor  ossis 
metacarpi  pollicis  and  the  extensor  primi  internodii  pollicis 
muscles.  Forced  abduction  of  the  thumb  will  reveal  the 


LOWER    EXTREMITY.  2G9 

depression  to  which  the  above  name  has  been  given.  The 
radial  artery  traverses  this  space  in  the  direction  of  a  line 
drawn  from  the  tip  of  the  styloid  process  of  the  radius  to 
the  head  of  the  metacarpal  bone  of  the  forefinger.  Its 
pulsations  may  be  felt. 

The  position  of  the  superficial  palmar  arch  nearly  corre- 
sponds to  a  line  drawn  across  the  palm  from  the  bottom  of 
the  cleft  of  the  thumb,  or  to  that  crease  in  the  palm  which 
runs  obliquely  and  transversely,  and  which  is  nearest  to 
the  carpus.  The  deep  palmar  arch  is  situated  posteriorly 
to  the  superficial  arch. 

LOWER   EXTREMITY. 

The  pulsations  of  the  external  iliac  artery  may  be  felt 
just  above  the  middle  of  Poupart's  ligament,  and  at  this 
point  the  artery  may  be  compressed  against  the  horizontal 
ramus  of  the  os  pubis. 

Poupart's  ligament  may  be  felt  as  a  rounded  cord,  most 
distinct  at  its  inner  extremity,  extending  from  the  anterior 
superior  spinous  process  of  the  ilium  to  the  spine  of  the 
pubes ;  the  spermatic  cord  crosses  it  obliquely  at  its  inner 
end,  which  constitutes  the  inferior  pillar  of  the  external 
abdominal  ring. 

The  general  outlines  of  Scarpa's  triangle,  unless  con- 
cealed by  adipose  tissue,  may  be  seen  in  the  upper  and 
anterior  part  of  the  thigh.  It  is  limited  by  Poupart's  liga- 
ment above ;  by  the  upper  border  of  the  adductor  longus 
muscle  on  its  inside,  and  by  the  upper  border  of  the  sarto- 
rius  muscle  on  the  outside.  Its  apex  is  about  four  inches 
below  Poupart's  ligament.  At  this  point  the  pulsations  of 
the  femoral  artery  may  be  felt,  and  it  is  here  that  the 
tourniquet  is  usually  applied  in  amputations  of  the  lower 
extremity. 

The  saphenous  opening  may  be  felt,  in  a  thin  subject,  just 
below  Poupart's  ligament.  Its  outer  border  corresponds 
to  the  inner  edge  of  the  femoral  artery.  An  enlarged 
gland  sometimes  conceals  it. 

The  femoral  artery  follows  a  course  indicated  by  a  line 
drawn  from  the  middle  of  Poupart's  ligament  to  the  pos- 
terior edge  of  the  inner  condyle.  At  the  lower  fourth  of 
the  thigh,  upon  the  inside,  a  tendinous  cord  m&y  be  felt 
along  its  inner  border.  This  is  formed  by  the  outer  border 
of  the  tendon  of  the  adductor  magnus  muscle,  and  con- 

23* 


270       IMPORTANT    ANATOMICAL    LANDMARKS. 

tains  the  aperture  called  Hunter's  canal,  through  which 
the  femoral  artery  passes  to  reach  the  popliteal  space. 
This  orifice  may  sometimes  be  felt  by  the  finger. 

The  patella  rests  upon  the  condyles  of  the  femur.  The 
tendon  of  the  triceps  extensor  muscle,  and  the  ligament 
of  the  patella  below,  divide  the  articulation  of  the  knee 
into  two  lateral  halves,  and  the  expansion  of  the  patella 
laterally,  divides  it,  to  a  certain  extent,  transversely.  If 
there  is  any  increase  of  the  synovial  fluid,  the  fulness  of 
the  capsule  will  be  most  obvious  above  and  below  the 
patella,  on  each  side  of  the  tendon  and  of  the  ligament. 
The  articulation  will  consequently  have  a  quadrilateral 
shape,  with  four  projections  corresponding  to  the  above- 
mentioned  localities. 

The  trochanter  major,  when  the  thigh  is  rotated,  describes 
an  arc  of  a  circle,  the  radius  of  which  is  equal  to  the  length 
of  the  head  and  neck  of  the  femur.  The  inner  condyle  be- 
ing on  the  same  plane  as  the  head  of  the  bone,  indicates 
always  the  direction  which  the  latter  assumes. 

The  sciatic  nerve  follows  a  course  indicated  by  a  line 
drawn  from  a  point,  midway  between  the  trochanter  major 
and  the  tuberosity  of  the  ischium,  to  the  upper  angle  of 
the  popliteal  space. 

The  popliteal  'space  is  a  diamond-shaped  depression  at 
the  posterior  aspect  of  the  knee-joint.  Its  lower  sides  are 
formed  by  the  prominences  of  the  two  separated  muscular 
bellies  by  which  the  gastrocnemius  muscle  arises.  Its 
upper  and  outer  side  is  formed  by  the  lower  extremity  of 
the  biceps  muscle.  Its  upper  and  inner  side  is  formed  by 
the  following  four  muscles,  enumerated  in  their  order  from 
within  outward ;  semi-membranosus,  semi-tendinosus,  gra- 
cilis,  and  sartorius. 

The  popliteal  artery,  extending  from  the  opening  in  the 
tendon  of  the  adductor  magnus,  to  the  upper  border  of  the 
soleus  muscle,  follows  a  line,  a  little  oblique,  from  within 
outward,  but  corresponding,  in  a  general  way,  to  the  long 
axis  of  the  popliteal  space.  It  is,  however,  a  trifle  nearer 
its  inner  than  its  outer  side.  The  artery  lies  too  deep  for 
its  pulsations  to  be  felt.  It  should  be  noticed  that  when 
the  leg  is  flexed,  a  bullet  might  traverse  'the  popliteal 
space,  or  the  ham-strings  be  divided,  without  wounding 
the  popliteal  artery;  but  that  this  could  not  happen  when 
the  limb  is  straight  and  extended  as  in  the  erect  position. 

The  anterior  tibial  artery,  in  the  leg,  follows  a  course 


LOWER    EXTREMITY.  271 

indicated  by  a  line  drawn  from  the  tubercle,  to  be  felt  on 
the  side  of  the  head  of  the  tibia,  to  a  point  at  the  ankle, 
midway  between  the  malleoli. 

The  pulsations  of  the  posterior  tibial  artery  may  be  felt 
at  a  point  midway  between  the  posterior  border  of  the 
inner  malleolus  and  the  tendo  Achillis. 

The  tendon  of  the  tibialis  anticus  lies  upon  the  instep,  and 
is  the  innermost  of  all  the  tendons  of  the  dorsum  of  the 
foot.  It  may  be  felt  between  the  ankle  and  the  inner 
border  of  the  metatarsal  bone  of  the  great  toe.  This 
tendon  is  often  divided,  subcutaneously,  for  the  relief  of 
deformity. 

The  tibialis  posticus  tendon  may  be  reached  behind  the 
inner  malleolus,  at  a  point  midway  between  the  anterior 
and  posterior  border  of  the  foot.  This  tendon  is  also  often 
divided,  subcutaneously,  for  the  relief  of  deformity. 

The  dorsalis  pedis  artery  follows  a  course  indicated  by 
a  line  drawn  from  a  point,  midway  between  the  malleoli, 
to  the  base  of  the  first  interosseous  space.  - 

The  prominence  of  the  head  of  the  first  metatarsal  bone 
may  be  felt  at  the  inner  border  of  the  foot.  On  its  outer 
border  the  projecting  tubercle  of  the  head  of  the  fifth 
metatarsal  bone  may  also  be  felt  and  seen.  These  are  im- 
portant landmarks  in  the  operation,  called  Lisfranc's,  for 
disarticulating  the  foot  at  its  tarso-metatarsal  articulation. 
Posterior  to  the  point  at  which  the  head  of  the  first  meta- 
tarsal bone  is  found,  may  be  felt  the  projecting  tubercle  of 
the  scaphoid  bone;  this  is  a  landmark  in  disarticulating 
the  foot  through  the  middle  of  the  tarsus,  in  what  is 
known  as  Chopart's  operation. 


INDEX. 


PAGE 

PAGE 

Abdomon, 

162 

Artery  —  aorta, 

arteries  of, 

176 

thoracic 

'  121 

superficial  fascia  of, 

163,  ItfS 

articular  of  the  hip, 

229 

Abdominal  regions, 

173,  266 

knee, 

236 

Acervulus, 

91 

auditory,  internal, 

99 

Acini, 

190 

auricular,  anterior, 

14,45 

Allantois, 

213 

posterior, 

14,  45 

Ampullae, 

98 

axillary, 

103,  104 

Anatomist's  snuff-box, 

149 

azygos  articular, 

237 

Andersch,  ganglion  of, 

37,  52 

basilar, 

80 

Annul  us  albidus, 

77 

brachial, 

106 

ovalis, 

117 

bronchial, 

121 

Anti-helix, 

14 

buccal, 

50 

Anti-tragus, 

14 

bulb,  of  the, 

201,  205 

Aorta,  abdominal, 

177 

calcanear, 

243 

arch  of, 

56,  114 

carotid,  common, 

42,  44,  56 

ascending, 

114 

external, 

44 

descending, 

114 

internal, 

30,  52,  81 

sinuses  or, 

119 

temporal  portion  of, 

65 

thoracic, 

121 

carpal,  radial, 

143,  149 

transverse, 

114 

ulnar, 

144 

Aponeurosis,  epicranial, 

16 

centralis  retinae, 

32 

pharyngeal, 

61 

cerebellar,  inferior, 

80 

temporal, 

25 

superior, 

80 

vertebral, 

128 

cerebral,  anterior, 

81 

Apparatus  ligamentosus  colli, 

75 

middle, 

81 

Appendices  epiploicae, 

184 

posterior, 

80 

Appendix  of  the  auricles, 

115 

anterior  cervical, 

58 

testicle, 

218 

ciliary, 

31,  32 

vermiforrnis  caeci, 

183 

circumdex,  anterior, 

lOi 

Aqueduct  of  Sylvius, 

91 

external, 

227,  230,  234 

Aqueductus  cochleae, 

99 

superficial, 

195 

vestibuli, 

97 

internal, 

228,  234 

Aqueous  humor, 

78 

ilii, 

166,  201 

Arachnoid  of  the  brain, 

79 

posterior, 

104 

spinal  cord, 

131 

coeliac, 

177 

Arbor  vitae  of  the  cerebellum, 

94 

colica,  d  extra, 

179 

uterus, 

221 

media, 

179 

Arch,  aortic, 

56,  114 

sinistra, 

179 

crural, 

197 

comes  nervi  ischiatici, 

231 

palmar,  deep, 

155 

phrenici, 

111 

superficial, 

152 

communicating,  anterior, 

81 

plantar, 

248 

of  the  foot, 

240 

Arches  of  the  palate, 

63 

hand, 

152 

Arciform  fibres, 

84 

posterior, 

81 

Arnold's  ganglion, 
Artery,  accessory  hepatic, 

49,  64 
178 

coronary  of  the  heart, 
lips, 

116,  119 
23 

acromial,  inferior, 

104 

cystic, 

'  178 

anastornotica  magna,  of  arm, 

107 

dental,  inferior, 

22,36 

of  thigh, 

228 

superior, 

50 

angular, 

23 

digital  of  the  foot, 

240,  248 

aorta,  abdominal, 

177 

hand, 

159 

arch  of, 

56 

dorsalis,  hallucis, 

240 

INDEX 


Artery,  dorsalis— 

!  Artery— 

nasi, 

31 

nasal, 

18,  31 

pedis, 

239,  2W 

nutrient  of  femur, 

228 

penis, 

205,  209 

of  tibia, 

243 

pollicis, 

149 

obturator,                            201, 

228,  229 

scapulae, 

139 

occipital,                          16,  45, 

130,  131 

epigastric, 

167,  201 

oesophageal, 

121 

superficial, 

163,  195 

ophthalmic, 

31 

•superior, 

111 

orbital, 

45,  51 

ethmoidal, 

31 

ovarian, 

ISO,  209 

facial,  . 

22,  44 

palatine,  posterior, 

50 

femoral, 

226 

palpebral, 

18,  31 

frontal, 

IS,  31 

pancreatico-duodenalis, 

178 

gastric, 

178 

parotidean, 

45 

gastro-duodenalis, 
epiploica  dextra, 

178 
178 

perforating  of  the  thigh, 
hand, 

228,  234 
155 

siuistra, 

178 

foot, 

248 

gl  uteal, 

209,  231 

pericardiac, 

111 

hemorrhoidal,  external, 

202 

perineal,  superficial, 

203 

middle, 

208 

peroneal, 

243 

superior, 

179,  209 

anterior, 

240 

hepatic, 

178 

pharyngeal,  ascending, 

45,  53 

accessory, 

178 

phrenic, 

177,  1W 

hyoid, 

44 

plantar,  external, 

246 

hypogastric, 

208,  256 

internal, 

246 

ileo-colic, 

i7»> 

popliteal, 

236 

iliac,  common, 

181 

posterior  scapular,               59, 

129,  139 

external, 

181,  201 

priuceps  cervicis, 

45,  130 

internal, 

207 

pollicis, 

104 

ilio-hunbar, 
infra-orbital, 

201,  209 
19,  51 

profuuda  cervicis, 
of  the  thigh, 

59,  129 
227 

innominata, 

66 

superior, 

107 

intercostal, 

121 

inferior, 

107 

anterior, 

111 

pterygoid, 

60 

external, 

121 

pterygo-palatine, 

50 

posterior  branches  of, 

129 

pudic  external,  superficial, 

195 

superior, 

59 

deep, 

195 

interosseous, 

144,  145 

internal,                       205,  208,  232 

anterior, 

145 

pulmonary, 

114 

of  foot. 

240 

pyloric, 

178 

of  hand, 

149,  155 

radial,                          141,  142, 

149,  154 

posterior 

145,  147 

radialis  indicis, 

154 

recurrent, 

148 

ranine, 

68 

ischiatic, 

208,  231 

recurrent  interosseous, 

148 

labial,  inferior, 

22 

radial, 

142 

lachrymal, 

-  31 

tibial, 

239 

laryngeal, 

44 

ulnar  anterior, 

144 

lateral  sacral, 

209 

posterior, 

144 

lateralis  nasi, 

.       23 

renal, 

180 

lingual, 

44,  68 

sacral,  lateral, 

209 

lumbar, 

181 

sacra  media, 

181 

posterior  branches  of, 

129 

scapular,  posterior,              59, 

129,  139 

malleolar, 

240 

sigmoid, 

179 

mammary,  external, 

104 

spermatic, 

180 

internal, 

59,  111 

spheuo-palatiue, 

50 

masseteric, 

50 

spinal, 

121,  135 

maxillary,  internal, 

60 

splenic, 

178 

median, 

144 

stylo-mastoid, 

45 

mediastinal, 

111 

subclavian, 

57 

meningea,  anterior, 

30 

submental, 

45,  47 

inferior, 

30,45 

subscapular,                        104, 

137,  138 

media, 

30,  50 

superflcialis  cervicis, 

58,  129 

parva, 

30,  50 

volse, 

143,  151 

posterior, 

30,58 

supra-orbital, 

31 

mesenteric,  inferior, 

179 

supra-renal, 

180 

superior, 

178 

supra-scapular,                    58, 

129,  138 

roetacarpal, 

149 

sural, 

236,  241 

metatarsal, 

240 

tarsal, 

240 

musculo-phrenic, 

111 

temporal. 

25,  45 

mylo-hyoid, 

50 

anterior, 

25,  45 

INDEX. 


275 


Artery,  temporal  — 

Calyx  of  the  kidney, 

192 

deep, 

v    50 

Canal,  crural, 

197 

middle, 

2.-),  45 

Fontana,  of, 

77 

posterior, 

2o,  45 

Hunter's, 

227,  229 

thoracic,  internal, 

111 

inguinal, 

169 

thoracica  acromialis, 

104 

lachrymal, 

17 

axillaris, 

104 

Nuck,  of, 

161,  2.">8 

inferior, 

104,  137 

Petit,  of, 

78 

superior, 

104 

Schlernm,  of, 

77 

thyroid  inferior, 

58,43 

semicircular, 

98 

lowest, 

58 

Capsule  of  Glisson, 

190 

middle, 
Neubauer,  of, 

56,58 
58 

of  the  knee-joint, 
Capsules,  supra-renal, 

231 
191 

superior, 

43,  44 

Caput  coli, 

183 

tibial  anterior,                    2 

36,  239,  242 

galinaginis, 

216 

posterior, 

242,  216 

Cartilage,  alar, 

21 

trausversalis  cervicis, 

58 

inter-articular  of  clavicle, 

54 

periuei, 

203 

jaw, 

49 

transverse  facial, 

23,45 

pubes, 

2'.0 

tympanic, 

50 

wrist, 

1150 

ul  liar, 

144 

lateral, 

20 

uterine, 

209 

of  nose, 

20 

vaginal, 

209 

of  Santorini, 

71 

vasa  brevia, 

178 

setnilunar, 

253 

vertebral,                            3( 

>,  58,  73,  80 

sesamoid, 

21 

posterior  branches  of, 

129 

thyroid, 

70 

vesical,  inferior, 

208 

Caruncula  lacrymalia, 

18 

middle, 

208 

Caruuculae  myrtiforrnes, 

220 

superior, 

208 

Cauda  equina, 

135 

Yidiau, 

50 

Cava,  vena,  inferior, 

111,  182 

Articulations,  acromio-clavicnlar,         l.>8 

superior, 

5:>,  113 

alto-ax  oidean, 

74 

Cavity,  pre-peritoneal, 

167 

carpo-inetacarpal, 

161 

visceral, 

172 

costo-  vertebral, 
coxo-femoral, 

156 

250 

Centrum  ovale  majus, 
minus, 

86 
86 

metacarpo-phalangeal, 

161 

Cerebellum, 

92 

occipito-atloid, 

74 

Cerebrum, 

85 

phalangeal, 

161 

Cerebro-spinal  fluid, 

80 

sternal, 

111 

Ceruminous  glands, 

15 

sti-ruo-clavicular, 

54 

Cervical  ganglia, 

53,  54,  59 

temporo  maxillary, 

48 

Chambers  of  the  eye, 

78 

tibio-femoral, 

251 

Chiasma,  . 

82 

tilno-tarsal, 

253 

Chorda;  tendinese, 

118 

Arytenoid  cartilages, 

71 

vocales, 

69 

Auditory  canal, 

94 

Willisii, 

27 

Auricle,  right, 

116 

Choroid, 

76,  77 

left, 

118 

plexus  of  fourth  ventricle, 

93 

Auriculo-ventricular  openings, 

117,  119 

lateral  ventricle, 

88 

Axilla, 

102 

third  ventricle, 

90 

Axis  coeliac, 

177 

Ciliary  ligament, 

77 

thyroid, 

08 

processes, 

77 

Circle  of  Willis, 

81 

Bands,  ventricular. 

69 

Circulation,  foetal, 

258 

Bartholiuus's  glands, 

220 

Clitoris, 

219 

Base  of  the  brain, 

85 

"Cochlea, 

98 

Bichat,  fissure  of, 

89 

Coeliac  axis, 

177 

Bifurcation  of  the  trachea, 

115 

Colon, 

183,  172 

Bladder, 

207,  213 

Colurnnse  carnese, 

118 

foetal, 

257 

Columns  of  Berlin, 

193 

Bone,  hyoid, 

70 

Morgagni, 

213 

Bone,  spongy, 

65 

spinal  cord, 

136 

turbinated, 

65 

the  vagina, 

221 

Brain, 

79,  81 

Commissure  of  spiual  cord, 

136 

Bronchi, 

115 

Commissures  of  braiu, 

90 

Brunner's  glands, 

185 

Concha, 

14 

Bulb  of  corpus  spongiosum, 

215 

Conjoined  tendon, 

165,  166 

Bulbous  portion  of  urethra, 

217 

Conjunctiva, 

17 

Con  us  a.rteriosus, 

118 

Cjecum, 

183 

Convolution  of  corpus  callosum, 

86 

Calamus  scriptorius, 

93 

Convolutions, 

86 

276 


INDEX. 


Cord,  spermatic, 

Ifi9 

Ear,  internal, 

97 

Cords,  ventricular, 

69 

middle, 

95 

vocal, 

69 

Ejaculatory  duct, 

214 

Cornea, 

76 

Eminentia  collateralis, 

88 

Cornna  of  lateral  ventricles, 

87 

teres, 

93 

Corona  glandis, 

216 

Encephalon,                                           79,  81 

Coronary  valve, 

117 

Endocardium, 

116 

Corpora  albicantia, 

85 

Epididymis, 

218 

Arantii, 

118,  119 

Epigastric  region, 

173 

cavernosa, 

215 

Epiglottidean  gland, 

71 

quadrigemina, 

91 

Epiglottis, 

71 

Corpus  callosum, 

85,  86 

Eustachian  tube,                                   62,  96 

nmbriatum, 

89,  222 

valve,                                           117, 

258 

geniculatum, 

91 

Eye, 

76 

olivare, 

84 

Eyelids, 

17 

pyramidale, 

84 

restiforine, 

84 

Falciform  border, 

196 

rhomboideum, 

94 

Fallopian  tubes, 

222 

spongiosum, 

215 

Falx  cerebelli, 

29 

striatum, 

87 

cerebri, 

27 

Corpuscles  of  the  spleen, 

186 

Fascia  cervical, 

38 

Cortical  substance  of  brain, 

86 

cribriform, 

of  kidney, 

193 

deep, 

196 

Covered  band  of  Keil, 

87 

iliaca, 

196 

Cowper's  glands, 

204,  217 

iufuudibuliform  of  inguinal  canal, 

109 

Cranial  nerves, 

33,  82 

of  crural  canal, 

197 

Cribriform  fascia, 

196 

lata, 

196 

Cricoid  cartilage, 

71 

leg  of  the, 

23  S 

Crico-tbyroid  membrane, 

71 

lumboruin, 

127 

Crista  of  the  vestibule, 

97 

obturator, 

210 

Crura  cerebelli, 

SI,  92 

palmar, 

151 

cerebri, 

84 

plantar, 

215 

of  the  diaphragm, 

194 

pelvic, 

210 

fornix, 

89 

periueal, 

202 

Crus  penis, 

205 

propria. 

198 

Crural  arch, 

197 

recto-vesical, 

210 

canal, 

197 

spermatic,                                    164, 

169 

septa  of, 

197 

superficial  of  abdomen,            163, 

I6S 

ring, 

197 

perineum, 

202 

Crystalline  lens, 

78 

thigh, 

195 

Cuneiform  cartilages, 

71 

tran  sversalis, 

1(19 

Cupola, 

98 

Femoral  hernia, 

196 

Cystic  duct, 

176,  190 

Fenestra  ovalis, 

95 

rotunda, 

95 

Dartos, 

217 

Fibres,  arciform, 

S4 

PetruKor  urinffi, 

213 

inter-columnar,                           164, 

16!) 

Decussation  of  anterior  pyramids,          84 

Fibro-cartilage,  iuter-articular  of  the 

Diaphragm, 

193 

clavicle, 

54 

larger  muscle  of  the, 

194 

of  the  jaw, 

49 

lesser, 

194 

knee, 

253 

Duct,  cystic, 

176,  190 

nose,                                        20 

,  21 

hepatic, 

176,  190 

pubes, 

250 

lactiferous, 

101 

wrist. 

]  60 

nasal, 

18,  66     Filum  terminale, 

134 

pancreatic, 

187     Fimbriated  extremity  of  Fallopian 

prostatic, 

216 

tube, 

222 

Rivinian, 

66 

Fissura  Glaseri, 

95 

Steno's, 

24 

Fissure  of  Bichat, 

89 

thoracic, 

65,  123,  195 

of  Sylvius,                                      81 

,  85 

Wharton's, 

47 

transverse  of  the  brain, 

89 

Ductus  arteriosus, 

114,  258 

Fissures  of  the  spinal  cord, 

136 

choledochus  communis, 

176,  190 

liver, 

1SS 

communis  ejacnlatorius, 
lymphaticus  dexter, 

214 

55,  123 

Floating  kidney, 
Fluid,  sub-arachnoid,                          80, 

193 
134 

venosus, 

257 

Foetal  circulation, 

258 

Duodenum, 

183,  185 

Foatus,  anatomy  of, 

256 

Dura  mater  of  the  brain, 

26 

Fold,  ary-epiglottidean, 

69 

spinal  cord, 

134 

recto-vesical, 

205 

recto-uterine, 

206 

Ear,  external, 

"~   13,  41 

semilunar  of  Douglass, 

167 

INDEX. 


211 


Fold  — 

Gland- 

vosico-nterine, 

206 

pineal, 

91 

Follicles  of  Lieberknhn, 

184 

pituitary, 

29,  85 

Foramen  caecum,  of  brain, 

84 

salivary, 

46,  66 

tongue, 

67 

socia  parotidis, 

24 

commune  anterius, 

90 

solitary, 

184 

posterius, 

90 

subliugual, 

66 

Muuro,  of, 
ovale. 

90 
258 

submaxillary, 
synovial  of  Havers, 

48 
251 

Soemmering,  of, 
Winslow,  of, 

78 
174 

thymus, 
ti-acheal, 

112,  258 
71 

Foramina  Thebesii, 

117 

Tyson's, 

216 

For  nix, 

89 

vulvar, 

220 

Fossa,  inguinal, 

170 

Glans,  clitoridis, 

219 

innominata, 

14 

penis, 

216 

ischio-rectal, 

fiOfi 

Glisson's  capsule, 

390 

nasal, 

65 

Graafian  vesicles, 

222 

naviculavis, 

217 

Gubernaculum  testis, 

257 

ovalis, 

117 

Guthrie's  muscle, 

210 

scaphoid, 

14 

Gyri, 

86 

Fourchette, 

219 

Gyrus  fornicatus, 

86 

Fovea  hemispherica, 

97 

semi-elliptica, 

97 

Hamulus  laminae  spiralis, 

98 

Frenum  epiglottidis, 

66 

Heart, 

113,  115 

of  lips, 

60 

foetal, 

258 

tongue, 

66 

Helicotrema, 

98 

prepuce, 

216 

Helix, 

14 

Hemispheres  of  the  brain, 

86 

Gall-bladder, 

190 

Hepatic  duct, 

176,  190 

Ganglia,  cervical, 

53,  54,  59 

Hey's  ligament, 

196 

lumbar, 

181 

Hernia,  congenital, 

171 

sacral, 

207 

crural, 

196 

thoracic, 

122 

direct, 

170,  171 

Ganglion,  Andersch,  of, 

37,52 

encysted, 

171 

Arnold's, 

49,  64 

femoral, 

196 

Gasserian, 

35 

inguinal, 

16S 

cervical,  inferior, 

51,  59 

oblique, 

170,  171 

middle, 

53 

caecum,  of  the, 

171 

superior, 

53 

Hesse  Ibacb,  triangle  of, 

171 

jugulare, 
leuticular, 

36 
34 

Hilus  of  the  kidney, 
liver, 

192 

189 

Meckel's, 

64 

spleen, 

186 

otic, 

49,  64 

Hippocampus  major, 

88 

petrosum, 

37,  52 

minor, 

M 

of  the  root, 

"    37 

Homer's  muscle, 

18 

semilunar, 

177 

Horseshoe  kidney, 

193 

spheno-palatine, 

64 

Hunter's  canal, 

227,  229 

submaxillary, 

47 

Hyaloid  membrane, 

79 

thyroid, 

53 

Hyoid  bone, 

70 

Genital  organs, 

267 

Hymen, 

220 

Genu  of  the  corpus  callosum, 
Gimbernat's  ligament, 

85 
196 

Hypochondriac  region, 
Hypogastric  region, 

173 
173 

Gland,  agmiuated, 

184 

Bartholinus's, 

220 

Ileo-caecal  valve, 

183 

bronchial, 

115 

Ilenm, 

183 

Brunner's, 

185 

Ineisura  cerebellL, 

93 

cernminous, 

15 

Incus, 

96 

Cowper's, 

204 

Infundibulura  of  the  brain, 

85 

duodenal, 

185 

heart, 

118 

epiglottidean, 

71 

kidney, 

192 

inguinal, 

163,  196 

Inguinal  canal, 

169 

labial, 

21 

fossae, 

170 

lachrymal, 
Lieberkuhn's, 

18 
184 

region, 
Inter-articular  cartilage  of  the 

.163,  173 
clav- 

mammary, 

101 

icle, 

54 

meibomian, 

17 

jaw, 

49 

mesenteric, 

179 

wrist, 

160 

Pacchionian, 

26 

Inter-columnar  fibres, 

164,  169 

parotid, 
Peyer's, 

21 
1S4 

Inter-peduncular  space, 
Inter-  vertebral  substance, 

85 
157 

24 

278 


INDEX. 


Intestinal  tube, 

183 

Ligaments  — 

Intestines,  foetal, 

257 

broad,  of  tlie  nterns, 

207,  221 

lutumescentia  gangliformis, 

36 

calcaneo-astragaloid 

254 

Iris, 

77 

cuboid. 

254 

Ischio-rectal  fossa, 

202 

scaphoid, 

2J1 

Island  of  Reil, 

85,  86 

capsular    of   the    articular 

pro- 

Isthmus  faucium, 

62 

cesses, 

158 

Iter  ad  infundibulum, 

90 

hip, 

850 

a  tertio  ad  quart  um  ventriculum, 

knee, 

251 

91,  93 

shoulder, 

159 

thumb, 

161 

Jejunum, 

183 

carpal, 

160 

Joint,  ankle, 

253 

carpo-metacarpal, 

161 

elbow, 

159 

check, 

75 

hip, 

250 

chondro-sternal, 

111 

lower  jaw, 

48 

common,  anterior, 

157 

knee, 

251 

posterior, 

157 

shoulder, 

159 

coccyx,  of  the, 

249 

wrist, 

160 

conoid, 

158 

coraco-acromial, 

158 

Kidneys, 

191 

clavicular, 

158 

foetal, 

257 

humeral, 

159 

pelvis  of, 

192 

coronary,  of  liver, 

188 

costal, 

111 

Labia  majors, 

219 

costo-clavicular, 

54 

minora, 

220 

transverse, 

156 

Labyrinth, 

97 

vertebral, 

156 

membranotrsy 

99 

xiphoid, 

112 

Lachrymal  canal, 

17 

cotyloid, 

251 

gland, 

18 

crico-thyroid, 

71 

punctum, 

18 

crucial, 

75 

sac, 

18 

of  knee, 

252 

Lacteals, 

185 

deltoid, 

253 

Lacuna  magna, 

217 

elbow,  of  the, 

160 

Lamina  einerea, 

85 

fibula,  of  the, 

253 

eribrosa, 

76 

Gimbernat's, 

196 

spiralis, 

98 

glosso-epiglottidean, 

66,  71 

Landmarks, 

260 

glenoid, 

159 

Large  intestine, 

183 

Key's 

196 

Larynx, 
nerves  of, 

68 

70 

hip-joint,  of  the, 
hyo-epiglottic, 

250 
71 

arteries  of, 

70 

ilio-femoral, 

250 

ventricles  of, 

69 

lumbar, 

249 

Lateral  tract, 

84 

interarticular  of  hip-joint, 

251 

ventricles, 

87 

of  ribs, 

156 

Lens,  crystalline, 

78 

interclavicular, 

54 

suspensory  ligament  of, 

78 

interosseous,  fibula,  of  the, 

253 

Lenticular  ganglion, 

34 

metacarpal  bones,  of  the 

161 

Lieberkuhn,  follicles  of, 

184 

metatarsal  bones,  of  the, 

254 

Ligamenta  brevia  of  the  fingers, 

154 

middle, 

157 

toes, 

247 

transverse, 

157 

subflava, 

158 

interspinous, 

158 

Ligaments,  acromio-clavicnlar, 

158 

intertransverse, 

158 

alar, 

252 

jaw,  of  the, 

48 

ankle,  of  the, 

253 

knee,  of  the. 

251 

annular,  anterior,  of  ankle, 

238 

larynx,  of  the, 

71 

external, 

244 

lateral,  of  the  ankle, 

253,  254 

internal, 

244 

elbow, 

159 

wrist,  anterior  of  the, 

147,  153 

jaw, 

48,49 

posterior  of  the, 

149 

knee, 

252 

anterior  of  knee, 

252 

phalanges,  foot, 

254 

of  ankle, 

253 

hand, 

161 

of  elbow, 

159 

wrist, 

160 

of  wrist, 
arcuatum  externum, 

160 
194 

liver,  of  the, 
lumbo-sacral, 

188 
249 

internum, 

194 

metacarpo-phalangeal, 

161 

astragalo-scaphoid, 

254 

metatarsal, 

254 

atlo-axoid, 

74 

mucous, 

253 

bladder,  of  the, 

207 

nuchse, 

126 

broad,  of  the  liver, 

172 

oblique, 

160 

INDEX. 

279 

Ligaments  — 

Lobes  of  the  brain, 

81 

obturator, 

250 

liver, 

188 

occipito-atloid, 

74 

prostate, 

214 

axoid, 

75 

lungs, 

121 

odontoid, 

75 

Lobule  of  the  ear, 

14 

orbicular, 

159 

Lobus  caudatus, 

1S9 

ovary,  of  the, 

222 

quadratus, 

189 

palpobral, 

17 

Spigelii, 

189 

patellae, 

252 

Locus  niger, 

94 

pelvis,  of  the, 
peroaeo-tibial, 

249 
252 

perforatus, 
Lumbar  fascia, 

85 
127 

phalangeal,  of  the  foot, 

255 

region, 

173 

hand, 

161 

Lungs, 

124 

plantar, 

251 

foetal, 

258 

posterior,  of  elbow, 

159 

Lymphatic  glands  of  abdomen, 

179 

of  wrist, 

160 

axilla, 

]02 

posticum  Winslowii, 

235,  232 

bronchial. 

115 

Poupart's 

164 

of  elbow, 

110 

pterygo-maxillary, 

61 

inguinal. 

163,  196 

pubic. 

250 

Lyra  of  the  fornix, 

S9 

Retzius,  of, 

238 

round,  of  the  liver, 

172 

Malleus, 

96 

uterus, 

221 

Mammary  gland, 

101 

sacro-coccygean, 

249 

Meatus  auditorius, 

14,  15 

sacro-iliac, 

249 

of  the  urethra,  female, 

220 

sacro-ischiatio,  greater, 

249 

male, 

216 

lesser, 

250 

Meatuses  of  the  nares, 

65 

shoulder,  of  the, 

159 

Meckel's  ganglion, 

.64 

stellate, 

156 

Meconium, 

257 

sternal, 

111 

Mediastinum,  anterior, 

112 

stern  o-elavicular, 

54 

posterior, 

120 

stylo-hyoid, 

51,  61 

testis. 

218 

stylo-maxillary, 
sub-pubic 

49    Medullary  substance  of  brain, 
250                   of  cerebellum, 

S6 
93 

supra-condyloid, 

109 

Medulla  oblongata, 

83 

supra-spiuons, 

158 

Meiboraian  glands, 

17 

tarsal, 

251 

Membrana  deutata, 

135 

tarso-metatarsal, 

251 

nictitans, 

IS 

teres, 

251 

tympani. 

94 

thyro  epiglottic, 

71 

secondary, 

95 

thyro-hyoid, 

70 

Membrane,  choroid, 

77 

transverse  of  the  crucial, 

75 

costo-coracoid, 

102 

acetabulum, 

251 

crico-thyroid, 

71 

atlas, 

75 

of  Desceinet, 

76 

fingers, 

151 

Demours, 

76 

knee, 

253 

hyaloid, 

79 

metatarsus, 

255 

interosseous,  of  forearm, 

160 

scapula, 

159 

of  leg, 

J53 

semilunar  cartilages,          253 

obturator, 

250 

trapezoid, 

158 

pituitary, 

66 

triangular, 

168,  204 

Schneiderian 

66 

tympanum,  of  the, 

97 

thyro-hyoid, 

m 

uterus,  broad,  of  the 

207,  221 

Membranous  urethra, 

217 

wrist,  of  the 

160 

labyrinth, 

97 

Ligamentura,  denticulatum, 

135 

Mesenteric  glands, 

179 

breve  plantae, 

254 

Mesentery, 

174 

longum  plantae, 

254 

Meso-colon,  transverse, 

174 

suspensorium,  of  odontoid 

process,  75 

Meso-caecum, 

174 

of  penis, 

163 

Mesorchium, 

258 

nuchae, 

126 

Meso-rectum, 

174 

Limbus  luteus, 

78 

Middle  ear,. 

95 

Linea  alba, 

163 

Mitral  valve, 

lift 

arcuata, 

164 

Modiolus, 

98 

Lineae  transversse,  of  fourth  ventricle,    93 

Mons  Veneris, 

219 

rectus  muscle, 

166 

Morsus  diaboli, 

222 

Liquor  Cotunnii, 

99 

MUSCLES, 

Scarpai, 

99 

abductor  indicl?, 

150 

Lithotomy, 

205 

minimi  digiti  pcdis, 

246 

Liver, 

187 

man  us, 

152 

foetal, 

257 

pollicis  pedis, 

246 

280 


INDEX. 


Muscles— 

Muscles,  flexor  — 

abductor  pollicis  mantis, 

151 

brevis  pollicis, 

10] 

acceleratores  urinae, 

203 

pedis, 

247 

accessorius, 

247 

carpi  radialis, 

141 

ad  sacro-lumbalem, 

130 

ulnaris, 

141 

adductor,  brevis, 

223 

brevis  digitorum, 

245 

lougus, 

226 

profuiidus, 

145,  254 

magnus, 

228 

sublimis, 

142,  153 

minimi  digiti  manus, 

152 

longiis  digitorum, 

243,  247 

pollicis  pedis, 

247 

pollicis,                   145, 

151,  154 

manus, 

154 

pedis, 

243,  247 

anconeus, 

147 

ossis  metacarpi  pollicis, 

151 

anti-tragicus, 

15 

minimi  digiti, 

152 

arytenoideus, 

68 

gastrocnemius, 

241 

attolleus  aurem, 

14 

gemellus,  inferior, 

233 

attrahens  aurem, 

13 

superior, 

233 

azygos  uvulse, 

63 

genio-h  yo-glossus, 

67 

basio-glossus, 

67 

geiiio-hyoid, 

47 

biceps,  of  the  thigh, 

234 

glosso-pharyngeus, 

61 

arm,                        105,  142, 

160 

gluteus  inaxiinus, 

230 

biventer  cervicis, 

131 

medius, 

230 

brachialis  anticus,                      106, 

142 

minimus, 

232 

buccinator, 

22 

gracilis, 

226 

bursalis, 

233 

Outline's, 

210 

cerato-glossus, 

67 

helicis,  major, 

15 

cervicalis  ascendens, 

131 

minor, 

15 

chondro-glossus, 

67 

Horner's, 

18 

ciliary, 

77 

hyo-glossus, 

67 

coccygeus, 

212 

iliacus  internus, 

200,  226 

coniplexus, 

131 

infra-costales, 

124 

compressor  nasi, 

20 

infra-spinatus, 

138 

urethra, 

211 

intercostal,  external, 

124 

constrictor  isthmi  faucium, 

64 

internal, 

12t 

medius, 

61 

interosseous,  dorsal,  of  the  hand,  150 

inferior, 

61 

foot, 

240 

superior, 

61 

palmar, 

155 

vaginse, 

205 

plantar, 

248 

coraco-brachialis, 

106 

interspinales, 

133 

corrugator  supercilii, 

17 

iutertransversales, 

73,  133 

cremaster, 

165 

larynx,  of  the, 

t;s 

crico-arytenoideus  lateralis, 

69 

latissimus  dorsi, 

126 

posticus, 

68 

laxator  tyrnpani, 

97 

thyroideus, 

68 

levator  anguli  oris, 

20 

crurseus, 

225 

scapulae, 

129 

deltoid, 

101 

ani, 

211 

depressor  anguli  oris, 

21 

glandulfe  thyroidese, 

43 

labii  inferioris, 

21 

labii  superiorisj 

19 

supercilii, 

17 

alaeque  nasi, 

19 

labii  snperioris  alseque  nasi, 

20 

inferioris, 

22 

detrusor  urinae, 

213 

levator  palati, 

63 

diaphragm, 

193 

palpebraj, 

32 

digastricus, 

46 

levatores  costarum, 

1S2 

ear,  of  the, 

13 

liugualijs,  inferior, 

67 

erector  clitoridis, 

205 

superior, 

67 

penis, 

203 

longissiruus  dorsi, 

131 

spinae, 

130 

longus  colli, 

72 

extensor  carpi  radialis  brevior, 

146 

lumbricales  of  the  foot, 

247 

longior, 

146 

hand, 

154 

ulnaris, 

147 

marsnpialis, 

23 

minimi  digiti, 

14' 

massa  carnea  Jacobi  Sylvii, 

247 

brevis  d  gitorum, 

239 

rnasseter, 

25 

commun.s  digitorura, 

147 

internal, 

48 

longus  digitorum, 

238 

multifldus  spinse, 

132 

indicis, 

149 

mylo-hyoid, 

47 

ossis  metacarpi  pollicis, 

148 

obliquus  externus, 

163 

proprius  pollicis, 

238 

Internal, 

165 

primi  internodii  pollicis, 

148 

inferior, 

32,  133 

secuudi  interuodii  pollicis, 

148                   superior, 

32,  133 

flexor  brevis  digiti  minimi, 

152            obturator  externus, 

229,  233 

pedis, 

248 

iuternns, 

212,  232 

INDEX. 


281 


Muscles  — 

Muscles  — 

occipito-frontalis, 

15,  131 

splenins  colli, 

128 

omo-hyoid, 

40,  129 

stapedius, 

97 

opponens  minimi  digiti, 

152 

sterno-hyoid, 

42 

pollicis, 

151 

sterno-mastoid, 

40 

orbicularis  oria, 

21 

sterno-thyroid, 

43 

palpebrae, 

16 

stylo-glossus, 

51 

palato-glossus, 

64 

stylo-hyoid, 

46 

pharyngeus, 
palmaris  brevis, 

63 
150 

stylo-pharyngeus, 
subclavius, 

51,61 
.    102 

longus, 

141 

sub-cruraeus, 

225 

poctineus, 

226 

subscapularis, 

137 

pectoralis  major, 

100 

supiuator  brevis, 

148 

minor, 

102 

longus, 

142 

peroneus  brevis, 

244 

supra-spinatus, 

138 

longus, 

244,  248 

temporal, 

26 

tertius, 

239 

tensor  palati, 

63 

plantaris, 

212 

tarsi, 

18 

platysrna  myoides, 

'38 

tympani, 

9T 

popliteas, 

243 

vaginaa  feinoris, 

224 

pronator  quadratus, 

14o 

teres  major, 

138 

radii  teres, 

141 

minor, 

139 

psoas  magnus, 

200,  226 

thyro-arytenoideus, 

m 

par  ran, 

200 

tliyro-hyoid, 

43 

pterygoid,  external, 

48 

tibialis  anticus, 

238 

internal, 

48 

posticus, 

244,  248 

pyrarnidalis,  of  the  abdomen 

107 

trachelo-rnastoid, 

131 

uasi, 

16 

tragicus, 

15 

pyriformis, 

212,  232 

transversalis  of  the  abdomen,        165 

quadratns  femoris, 

233 

colli, 

131 

lumborum, 

200 

pedis, 

248 

menti, 

21 

transverse,  of  the  ear, 

15 

quadriceps  extensor  cruris, 

22J 

trausversus  perinei, 

203,  205 

rectus  abdominis, 

166 

alter, 

203 

capitis  anticus  major, 

72 

trapezius, 

126 

minor, 

72 

triangularis  menti, 

.   21 

lateralis, 

72 

sterni, 

110 

posticus  major, 

133 

triceps  extensor  cruris, 

225 

minor, 

133 

cubiti, 

139 

femoi-is, 

224 

trochlearis, 

32 

external,  of  the  eye, 

32 

ureters,  of  the, 

21J 

inferior, 

32 

vastus  externus, 

22t 

internal, 

32 

interuus, 

225 

superior, 

32 

Wilson's 

211 

sternalis, 

167 

zygomaticus  major, 

20 

retrahens  aurem. 

14 

minor, 

20 

rhomboideus  major, 

128 

Musculi  pectinati, 

117 

minor, 

127 

risorius  Santorini, 

22 

Nares, 

65 

sacro-lumbalis, 

130 

Nasal  duct, 

18,  66 

salpingo-pharyngeus, 

62 

fossae, 

65 

sartorius, 

224 

Nates  of  the  brain, 

91 

scalenus  anticus, 

73 

Nerves,  abdominal, 

177,  199 

medius, 

73 

abducens, 

36,  82 

posticus, 

73 

accessory  obturator, 

199 

semi-spinalis, 

132 

spinal,                   37, 

41,  52,  S3,  135 

colli, 

132 

acromial, 

40 

dorsi, 

132 

auditory. 

36,  83,  99 

semi-membranosus, 

234 

auricularis  maguus, 

14,  39 

semi-tendinosus, 

234 

posterior, 

14,23 

serratus  maguus, 

137 

auriculo-temporal, 

24,  49 

posticus  inferior, 

128 

bracliial, 

59,  102 

superior, 

128 

buccal, 

24 

soleus, 

242 

cardiac, 

52,  120 

sphincter  ani, 

203 

inferior, 

59 

interims, 

203 

middle, 

53 

vosicae, 

213 

superior, 

53 

spinalis  dorsi, 

131 

cervical  anterior, 

39 

spleuius, 

128 

posterior, 

130 

capitis, 

128 

cervico-facial, 

23 

24* 


282 


INDEX. 


Nerves — 

chorda  tympani,  47,  50,  95 

circumflex,  108 

clavicular,  40 

coccygeal,  210 

cochlea  r,  36,  99 

communicans  uoni,  40,  42 

peronei,  236 

poplitei,  236 

cranial  33,  82 

cVural,  199,  223 
cutaneous,  of  the  back, 

external,  of  arm,  107 
th<gh,                       199,  223,  234 

internal,  108 

lesser,  108 

middle  posterior,  230,  234 

musculo,  107 

plantar,  243 

dental,  inferior,  21,  50 

superior, 

deficendens  noni,  41,  47 

digastric,  46 

digital,  of  the  foot,  237,  247 

hand,  146,  150,  153 

dorsal,  130 

dorsalis  penis,  203,215 

eighth  pair,  36,  83 

facial,  23,  36,  S3 

fifth  pair,  3.3,  82 

first  pair,  33,  82 

fourth  pair,  31,  82 

frontal,  35 

gastric,  120 

genito-crural,  199,  223 
glosso-pharyugeal,            36,  52,  68,  83 

•gluteal,  210,  231 

gustatory,  47,  50,  68 
hypo-glossal,                 37,  47,  50,  68,  83 

inferior  maxillary,  36 

infra-maxillary,  21 

infra-orbital,  39,  35 

intercostal,  122 

intercosto-humeral,  108,  123 

interosseous,  anterior,  143,145 

posterior,  108,  148 

Jacobson's,  37 

lachrymal,  35 

larynx,  of,  70 
laryngeal,  recurrent,             56,  70,  120 

superior,  52,  70 

lumbar,  130 

lumbo-sacral,  200,  210 

malar,  23 

masseteric,  49 

maxillary,  inferior,  36 

superior.  35 
median,                108,  143,  151,  152,  153 

molles,  53 

motor  oculi,  34,  82 
muscular,  superior,  of  the  bra- 

chial  plexus,  102 

inferior,  102 

musculo  cutaneous,  of  arm,  107 

leg,  237,  240 

thigh,  199,  166 

musculo-spiral,  108 

rnylo-hyoid,  47,  50 

nasal,  35 

naso-palatine,  64 


Nerves — 

ninth  pair, 
obturator, 
occipitalis  major, 

minor, 
cesophageal, 
olfactory, 
ophthalmic, 
optic, 
orbitar, 
palatine, 


37,  83 

19f),  210,  22S,  234 

14,  16,  130,  131 

14,  39 

120 

33,  82 

35 

33,  82 
35 
61 


palmar,  superficial,  143 

par  vagum,  37,  S3 

perforans  Casserii,  107 

perinea!  cutaneous,  203 

peroneal,  235 

cutaneous,  237 

petrosus  superficialis  major,  65 

minor,  64 

pharyrigeal,  52 

phrenic,  40,  56,  112 

plantar,  cutaneous,  243 

external,  246 

internal,  246 
pneumogastric,   37,  52,  55,  83,  120,  185 

popliteal,  236 

portio  dura,  36 

mollis,  36 

pterygoid,  external,  50 

internal,  50 

pudic,  internal,  203,  210 

pulmonary,  120 

radial,  143,  146 

recurrent,  laryngeal,  56,  70,  120 

renal,  193 

sacral,  130 

saphena,  external,  236,  238,  241 

long,  223 

short,  223,  236 

sciatic,  210,  231,  235 

lesser,  210,  230,  234 

sc  rot  ill,  199 

second  pair,  33,  82 

seventh  pair,  36,  83 

sixth  pair,  ,36,  82 
spermatic, 

sphe  no-palatine,  50 

spinal,  135 
spinal  accessory,        37,  41,  52,  S3,  135 

splanchnic,  greater,  122 

lesser,  122 

renal,  122 

stylo-hyoid,  46 

sub-occipital,  73,  133 

subscapular,  103,  137 
superficialis  colli, 

superior  maxillary,  35 

supra  maxillary,  «  24 

orbital,  17,  35 

scapular,  103,  123,  138 

sympathetic,  53,  122 

prevertebral  portion  of, 

vertebral  portion  of,  122 

temporal,  23 

temporo-facial,  23 

third  pair,  34,  82 

thoracic,  long,  103,  137 

short,  103 

tibial,  anterior,  237,  240 

posterior,  237,  243 


INDEX. 


283 


Nerves  — 

Pia  mater  of  the  spinal  cord, 

134 

trifacial, 

35,  82 

Pillars  of  the  palate, 

63 

trochlearis, 

34,  §2 

abdominal  ring, 

164,  169 

tympanic, 

37 

diaphragm, 

194 

iilnar,                    10S,  144,  146, 

150,  155 

Pineal  body, 

91 

vestibular, 

36,99 

Pinna, 

14 

Vidian, 

64 

Pituitary  body, 

29,  85 

Wrisberg, 

108 

membrane, 

66 

intermediate  portion  of, 

83 

Platysina  myoides, 

38 

Nose,  cartilages  of. 

20 

Pleura, 

120,264 

Nuck,  canal  of, 

171,  258 

Plexus,  abdominal, 

177 

Nymphse, 

220 

aortic, 

179 

brachial, 

59,  102 

(Esophagus, 

62,  121 

cardiac, 

122 

Omentum,  gastro-splenic, 

174 

deep, 

ue 

great, 

172,  174 

superficial 

116 

lesser, 

i/l 

carotid, 

31 

Openings  in  the  diaphragm, 
Optic  commissure, 

KM 

82 

cavernous, 
cervical,  anterior, 

31 
39 

thai  am  us, 

88,91 

posterior, 

130 

tract, 

82 

choroid, 

88 

Oraserrata, 

78 

hepatic, 

190 

Orbicular  process, 

96 

hemorrhoidal, 

207 

Orbiculare,  os, 

96 

hypogastric, 

207 

Orbit,  arteries  of, 

31 

1-1 
lumbar, 

199 

muscles,  of, 

32 

mesenteric, 

179 

nerves  of, 

35,  36 

ovarian, 

207 

Os  orbiculare, 

96 

phrenic, 

177 

Os  uteri, 

221 

pueumogastric, 

120 

internum, 

221 

prostatic, 

207,  214 

Otoconites, 

99 

pterygoid, 

51 

Ovaries, 

222 

pulmonary, 

122 

foetal, 

258 

renal, 

ISO 

sacral, 

210 

Pacchionian  glands, 

26 

solar, 

177 

Palate,  pillars  of, 

63 

spermatic, 

ISO,  219 

arches  of, 

63 

splenic, 

186 

hard, 

63 

supra-renal, 

177,  191 

soft, 

63 

•  uterine, 

207 

Palmar  arch,  deep, 

vaginal, 

207 

superficial, 

152 

vesical, 

207 

Palpebral  ligaments, 

17 

P,lica  semilunaris, 

18 

Pancreas, 

187 

Pomum  Adami, 

70 

lesser, 

18? 

Pons  Tarini, 

99 

Papillse  of  the  tongue, 

66 

Varolii, 

84 

caliciform, 

67 

Popliteal  space, 

235 

circuinvallatse, 

67 

Portal  vein, 

176 

conical, 

66 

Portio  dura, 

36 

filiform, 

66 

mollis, 

36 

fungi  form, 

66 

Porus  opticus, 

78 

kidney, 

192 

Position  of  aotrum, 

262 

Parietes  of  abdomen, 

162 

aorta, 

265 

Parotid  gland, 

24 

anatomist's  snuff-box, 

269 

Par  vagum, 

37,  S3 

arch,  deep  palmar, 

269 

Peduncles  of  the  cerebellum, 

92 

superficial  palmar, 

269 

corpus  callosum, 

85 

artery  axillary, 

268 

pineal  gland, 

91 

brachial, 

268 

Pelvis,  viscera  of, 

206,  212 

carotid, 

263 

Penis, 

215 

dorsalis  pedis, 

271 

Pericardium, 

113 

epigastric, 

2«6 

Perineal  centre, 

203 

facial, 

262 

Perineum, 

202 

femoral, 

26!) 

Peritoneum, 

173,  205 

gluteal, 

265 

reflections  traced, 

174,  205 

iliac,  external, 

26!) 

Pes  anserinus,  of  the  face, 

24 

innominate, 

2H  I 

knee, 

235 

meningeal,  middle, 

MO 

hippocampi,          « 
Peyer's  glauds, 

88 
184 

popliteal, 
radial, 

270 
868 

Pharynx, 

60 

rauine, 

262 

Pia  mater  of  the  brain, 

80 

subclavian, 

263 

284 


INDEX. 


Position  of— 

Process  — 

artery,  superficialis  volse, 

268 

supra-condyloid, 

106,  141 

thoracic,  inferior, 

267 

interior  vermiform, 

92 

tibial,  anterior, 

i;71 

superior  vermiform, 

92 

posterior, 

271 

Processus  auditorius, 

94 

ulnar, 

268 

cochlearitormis, 

96 

articulation,  medio-tarsal, 

271 

ad  medullam, 

93 

tarso-metaiarsal, 

271 

ad  pontem, 

92 

canal,  lachrymal, 

261 

e  cerebello  ad  testes, 

92 

cartilage,  cricoid, 

263 

vaginalis  peritonei, 

258 

xiphoid, 

265 

Promontory, 

95 

cauda  equiua, 

265 

Prostate, 

214 

colon, 

265 

Prostatic  urethra, 

216 

duct,  nasal, 

261 

Pulmonary  artery, 

114 

parotid, 

261 

plexus, 

122 

Rivinian, 

262 

vein 

114 

Steno's, 

261 

PuW  um  lac  ry  male, 

18 

Whartouian, 

262 

Pylorus, 

186 

epididymis, 

267 

Pyramid, 

96 

epiglottis, 

267 

Pyramids,  anterior, 

84 

Eustachian  tube, 

261 

Malpighi,  of, 

192 

foramen,  infra-orbital, 

260 

posterior, 

84 

mental, 

262 

supra-orbital, 

260 

Receptaculum  chyli, 

194 

heart, 

264 

Rectum 

173,  212 

valves  of, 

264 

Regions,  abdominal, 

173,  266 

ligament,  Poupart's, 

269 

inguinal, 

168 

linea  alba, 

265 

Reil,  island  of, 

85 

arcuata, 

265 

Rete  painpiniforme, 

219 

lung,  margin  of, 

264 

Retina 

78 

nerve,  musculo-spiral, 

268 

Rima  glottidis, 

69 

sciatic, 

268 

Ring,  abdominal,  external, 

164 

ulnar, 

270 

internal, 

169 

nipple, 

264 

crural, 

197 

opening,  saphenous, 

269 

Rivinian  ducts, 

66 

patella, 

270 

Root  of  the  lung, 

115,  125 

popliteal  space, 

270 

Roots  of  the  spinal  nerves, 

135 

Poupart's  ligament, 

269 

Rostrum, 

85 

process,  coracoid, 

^64 

posterior  superior  spinous  of 

Sac,  lachrymal, 

IS 

ilium, 

265 

Saccule, 

99 

prostate, 

267 

Sacculus  laryngis, 

69 

radius,  head  of, 

268 

Saphenous  opening, 

196 

ring,  external  abdominal, 

266 

Scala  tympani, 

99 

sac,  lachrymal. 

261 

vestibuli, 

99 

saphenous  opening, 

269 

Scarpa,  triangle  of, 

226 

scapula, 

265 

Schaeiderian  membrane, 

66 

Scarpa's  triangle, 

269 

Sclerotic, 

76 

sinus,  lateral, 

260 

Scrotum, 

217 

longitudinal, 

2,0 

Semicircular  canals, 

98 

space,  popliteal, 

270 

Semilunar  fold  of  Douglass, 

167 

tendon  of  tibialis  anticus, 

271 

valves, 

US,  119 

posticus, 

271 

Septa  of  crural  canal, 

197 

tonsil, 

262 

Septum  of  the  auricles, 

US 

trachea,  bifurcation  of,             264, 

265 

ventricles, 

119 

rings  of, 

263 

cruralei 

197 

triangle,  Scarpa's, 

269 

lucidum, 

89 

trochanter  major, 

270 

nasi, 

21,  65 

tube,  Eustachian, 

261 

of  the  tongue, 

67 

tuberosity  of  humerus, 
valves,  cardiac, 

267 
264 

Sheath  of  the  carotid  artery, 
flexor  tendons, 

41 
153,  216 

vein,  cephalic, 

207 

penis, 

216 

external  jugular, 

263                   rectus  muscle, 

167 

ranine, 

262    Sigmoid  flexure, 

173 

vas  defereus, 

267            valves, 

118,  119 

Poupart's  ligament, 

164    Sinuses  of  the  aorta, 

119 

Preperitoueal  cavity, 

167 

dura  mater, 

27 

Prepuce  of  the  clitoris, 

219 

pulmonary  artery, 

118 

penis, 

215 

uterus, 

221 

Process,  orbicular, 

96            Valsalva,  of, 

119 

INDEX. 

285 

Sinus,  basilar, 

29    Tapetum  oculi. 

77 

cavernous 

•     29 

Tarsal  cartilages, 

17 

circular, 

29 

Tendo  Achillis, 

241 

coronary, 

llfi 

ocnli, 

17 

lateral, 
longitudinal,  inferior, 

128 

29 

Tendon,  central,  of  diaphragm, 
conjoined, 

194 

165,  166 

superior, 

29 

Tentorium, 

27,  28 

occipital, 

29 

Testes, 

217 

petrosal,  inferior, 

28 

cerebri, 

91 

superior, 

28 

descent  of, 

257 

pocularis, 

216 

Thalamus  opticus, 

88,91 

prostatic, 

216 

Thoracic  duct, 

55,  123 

straight, 

27 

Throat,  exploration  of, 

262 

transverse, 

29 

Thymus  gland, 

112 

Small  intestines, 

183 

Thyro-hyoid  membrane, 

63 

Soft  palate, 

63 

Thyroid  axis, 

58 

Soemmering,  foramen  of, 

78 

cartilage, 

70 

Space,  interpeduucular, 

85 

body, 

43 

popliteal, 

235 

Tongue, 

66 

posterior  perforated, 

85 

Tonsil, 

63 

anterior  perforated, 

86 

Torcular  Herophili, 

27 

sub-arachnoid, 

80,  134 

Trabeculse, 

216 

Speculum  of  Van  Helinont, 

194 

Trachea, 

71 

Spermatic  cord, 

219 

bifurcation  of, 

115 

fascia, 

164,169 

Tract,  lateral, 

84 

Spheno-palatine  ganglion, 
Spinal  arteries, 

64 
135 

optic, 
Tragus, 

82 
14 

cord, 

134,  136 

Triangle  of  Hesselbach, 

171 

nerves, 

135 

of  Scarpa, 

226 

veins, 

136 

Triangles  of  the  neck, 

41 

Spleen, 
supplementary, 
Spongy  portion  of  the  urethra, 
Stapes, 

186 
1S7 
217 
96 

Triangular  ligament, 
Tricuspid  valve, 
Trigonum  of  the  bladder, 
Tube,  Eustachiau, 

204 
118 
213 
62 

Steuo's  duct, 

24 

Tuber  cinoreum, 

85 

Stomach, 

185 

Tubuli  galactophori, 

101 

Structure  of  bladder, 

213 

seminiferi, 

218 

cornea, 

76 

uriniferi, 

192 

intestinal  tube, 

184 

Tunica  albuginea, 

218 

kidney, 

192 

vaginalis, 

218 

liver, 

190 

Tympanic  bone, 

95 

lungs, 

125 

Tympanum, 

14,  94 

esophagus, 

122 

Tyson's  glands, 

216 

ovaries, 

222 

parotid  gland, 

24 

Umbilical  region, 

173 

prostate, 

215 

Urachus, 

213 

spleen, 

186 

Ureter, 

192 

stomach, 

186 

Urethra,  male, 

216 

testicle, 

218 

female, 

220 

tongue, 

66 

Uterus, 

221 

trachea, 

71 

Utricle, 

f-9 

uterus, 

221 

Uvea, 

77 

vagina, 

220 

Uvula  of  the  bladder, 

213 

vesiculse  seminales, 

214 

palate, 

63 

Striae  longitudinales, 

86 

Subarachnoid  space, 

80 

Vagina, 

220 

Subliugual  gland, 

66 

columns  of  the, 

221 

Submaxillary  gland, 

46 

Vallecula, 

92 

Substantia  perforata, 

87 

Valsalva,  sinuses  of, 

119 

Superficial  fas-cia,  of  abdomen, 

163,  168 

Valve,  aortic, 

119 

of  thigh, 

195 

arachnoid, 

93 

Supra-renal  capsules, 

191 

coronary, 

117 

Suspensory  ligament  of  liver, 

188 

Eustachian, 

117,  258 

of  penis, 

it;:? 

ilio-csecal, 

183 

Symphysis  pubes, 

250 

mitral, 

119 

Syuovial  membrane  of  knee, 

252 

pyloric, 

186 

jaw, 

49 

semilunar, 

118,  119 

sigmoid. 

118 

Tscnia  semicircularis, 

ss 

tricuspid, 

118 

hippocampi, 

89 

venous, 

223 

286 


INDEX 


Valve— 

Veins- 

Vieussens, 

92 

renal, 

182 

Valvulae  conniventes, 

184 

saphena,  external, 

241 

Vasculum  aberraus, 

218 

internal, 

196,  223,  237 

Vas  deferens, 

214,  219 

spermatic, 

181,  182,  210 

Veins,  axillary, 

102 

splenic, 

176 

azygos  major, 

123,  182,  195 

subclavian, 

M 

rniaor, 

123,  182,  195 

supra-renal, 

182 

basilic, 

105 

Thehesii, 

117 

cardiac, 

116 

thyroid, 

M 

cava,  inferior, 

114,  182 

ulnar, 

109 

superior, 

55,  113 

umbilical, 

2/>7 

cephalic, 

10.5 

uterine, 

221 

internal, 

51 

vertebral, 

55 

coronary, 

116 

Velum  interpositnm, 

89 

dorsalis  penis, 

215 

pendulum  palati, 

63 

epigastric, 

163 

Venae  Galeni, 

27,  90 

facial, 

23 

Venesection, 

109,  268 

femoral, 

226 

Ventricle  of  the  brain,  fifth, 

89 

Galeni, 

27 

fourth, 

93 

gastric, 

176 

lateral, 

87 

hemorrhoidal, 

210 

third, 

90 

hepatic, 

182 

Ventricles  of  the  brain, 

87 

iliac, 

182 

heart, 

117,  119 

innominata, 

55,  112 

of  the  larynx, 

69 

jugular,  anterior, 
external, 

39 
38 

Vermiform  processes, 
Vertebral  aponeurosis, 

92 
128 

internal, 

51,  55 

Veru  montanum, 

216 

lumbar, 

182 

Vesictilse  seminales, 

214 

maxillary,  internal, 

51 

Vestibule, 

97 

median, 

109 

Villi, 

185 

basilic, 

109 

Vieussens,  valve  of, 

92 

cephalic, 

109 

Vincula  subflava, 

104 

mesenieric,  inferior, 

176 

Vitreous  humor, 

179 

superior, 

176 

Vulva, 

219,  267 

ophthalmic, 

29 

ovarian, 

210 

Wharton's  duct, 

47 

phrenic, 

182 

Whartonian  gelatine, 

258 

popliteal, 

236 

Willis,  circle  of, 

81 

portal, 

176 

Wilson's  muscle, 

211 

profunda, 

228 

Wrisberg,  nerve  of, 

108 

prostatic, 

214 

pulmonary, 
radial, 

114 
109 

Zone  of  Zinn, 
Zouula  ciliaris, 

78 
78 

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ANDERSON    (McCALL).     ON   THE   TREATMENT   OF   DISEASES 
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•pLOXAM    (C.  L.)      CHEMISTRY,   INORGANIC    AND    ORGANIC. 
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•DEINTON  (WILLIAM).    LECTURES  ON  THE  DISEASES  OF  THE 
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1  vol.  8vo.     Cloth,  $3  25. 

BKTJNTON  (T.   LAUDER).     A   MANUAL  OF   MATERIA   MEDIC  A 
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BIGELOW  (HENRY  J.)     ON  DISLOCATION  AND  FRACTURE  OF 
THE  HIP,  with  the  Reduction  of  the  Dislocations  by  the  Flexion  Me- 
thod.    In  one  8vo.  vol.  of  150  pp.,  with  illustrations.     Cloth,  $2  50. 
BASHAM  (W.  R.)     RENAL  DISEASES  ;  A  CLINICAL  GUIDE  TO 
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•RTJMSTEAD    (F.   J.)    THE    PATHOLOGY   AND   TREATMENT    OF 
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gations upon  the  subject.     Third  edition,  revised  and  enlarged,  with 
illustrations.     1  vol.  8vo.,  of  over  700  pages.     Cloth,  $5  ;  leather,  $6. 
AND  CULLEEIEE'S  ATLAS  OF  VENEREAL.     See  "CULLE- 

RIER." 

BARLOW    (GEORGE   H.)     A    MANUAL   OF    THE  PRACTICE    OF 
MEDICINE.     1  vol.  8vo.,  of  over  600  pages.     Cloth,  $2  50. 
BAIED  (ROBERT).    IMPRESSIONS  AND  EXPERIENCES  OF  THE 
WEST  INDIES.     1  vol.  royal  12mo.     Cloth,  75  cents. 
BAENES    (EOBEET).     A   PRACTICAL   TREATISE   ON   THE  DIS- 
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with  169  illustrations.     Cloth,  $5  ;  leather,  $6.     (Just  issued.) 
TDEYANT    (THOMAS.)      THE   PRACTICE   OF    SURGERY.     In   one 
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tions.    Cloth,  $6  25  ;  leather,  $7  25.     (Jiist  issued.) 
BLANDFOED  (G.  FIELDING).   INSANITY  AND  ITS  TREATMENT. 
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471  pages.     Cloth,  $3  25. 

BELLAMY'S  MANUAL  OF  SUEGICAL  ANATOMY.  With  numerous 
illustrations.  In  one  royal  ]2mo.  vol.  Cloth,  $2  25.  (Just  issued.) 
BOWMAN  (JOHN  E.)  A  PRACTICAL  HAND-BOOK  OF  MEDICAL 
CHEMISTRY.  Edited  by  C.  L.  Bloxam.  Sixth  American,  from 
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rous illustrations.     1  vol.  royal  12mo.  of  350  pages.     Cloth,  $2  25. 
CHAMBERS  (T.  K.)     THE  INDIGESTIONS ;  OR,  DISEASES  OF  THE 
V     DIGESTIVE     ORGANS    FUNCTIONALLY    TREATED.       Third 
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of  over  300  pages.     Cloth,  $3  00. 

RESTORATIVE   MEDICINE.     An   Harveian    Annual  Oration 

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In  one  small  12mo.  volume.     Cloth,  $1  00. 

PARSON  (JOSEPH)  .   A  SYNOPSIS  OF  THE  COURSE  OF  LECTURES 

V  ON  MATERIA  MEDICA  AND  PHARMACY,  delivered  in  tho  Uni- 
versity of  Pennsylvania.  Fourth  and  revised  edition.  1  vol.  8vo. 
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flOOPER  (B.  B.)    LECTURES  ON  THE  PRINCIPLES  AND  PRACTICE 
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flARPENTER  (WM.  B.)     PRINCIPLES  OF  HUMAN  PHYSIOLOGY, 
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PRINCIPLES  OF  COMPARATIVE  PHYSIOLOGY.     New  Ame- 
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PRIZE  ESSAY  ON  THE  USE  OF  ALCOHOLIC  LIQUORS  IN 

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HHRISTISON  (ROBERT).  DISPENSATORY  OR  COMMENTARY  ON 

V    THE    PHARMACOPOEIAS    OF    GREAT    BRITAIN    AND    THE 

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nearly  700  pages.     Cloth,  $4  ;  leather,  $5. 

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pULLERIER  (A.)     AN  ATLAS  OF  VENEREAL  DISEASES.     Trans- 
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very  handsome  Svo.  vol.  of  over  700  pp.  Cloth,  $5  25  ;  leather,  $6  25. 

DAVIS  (F.  H.)  LECTURES  ON  CLINICAL  MEDICINE.  Second 
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(Now  ready.) 

DE  JONGH,  ON  THE  THREE  KINDS  OF  COD-LIVER  OIL.  1  small 
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DEWEES  (W.  P.)  A  TREATISE  ON  THE  DISEASES  OF  FEMALES. 
With  illustrations.  In  one  Svo.  vol.  of  536  pages.  Cloth,  $3. 

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MENT OF  CHILDREN.  In  one  Svo.  vol.  of  548  pages.  Cloth,  $2  80. 

DRUITT  (ROBERT).  THE  PRINCIPLES  AND  PRACTICE  OF  MO- 
DERN SURGERY.  A  revised  American,  from  the  eighth  London 
edition.  Illustrated  with  432  wood  engravings.  In  one  Svo.  vol. 
of  nearly  700  pages.  Cloth,  $4 ;  leather,  $5. 

DTJNGLISON  (ROBLEY).  MEDICAL  LEXICON;  a  Dictionary  of 
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large  Svo.  vol.  of  770  pages.  Cloth,  $4. 

DE  LA  BECHE'S  GEOLOGICAL  OBSERVER.  In  one  large  Svo.  vol. 
of  700  pages,  with  300  illustrations.  Cloth,  $4. 

DANA  (JAMES  D.)  THE  STRUCTURE  AND  CLASSIFICATION  OF 
ZOOPHYTES.  With  illustrations  on  wood.  In  one  imperial  4to.  vol. 
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-PLLIS    (BENJAMIN).      THE    MEDICAL    FORMULARY.      Being   a 
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the  most  eminent  physicians  of  America  and  Europe.     Twelfth  edi- 
tion, carefully  revised  by  A.  H.  Smith,  M.  D.     In  one  Svo.  volume 
of  374  pages.     Cloth,  $3. 

TIRICHSEN  (JOHN).   THE  SCIENCE  AND  ART  OF  SURGERY. 

•"     A  new  and  improved   American,  from  the  sixth  enlarged  and  re- 
vised London  edition.    Illustrated  with  630  engravings  on  wood.    In 
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•ENCYCLOPAEDIA  OF  GEOGEAPHY.     In  three  large  Svo.  vols.     Illus- 
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PENWICK    (SAMUEL.)     THE   STUDENTS'   GUIDE   TO  MEDICAL 
-L      DIAGNOSIS.     From  the  Third  Revised  and  Enlarged  London  Edi- 
tion.    In  one  vol.  royal  12mo.,  with  numerous  illustrations.     Cloth, 
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FISKE  FUND  PRIZE  ESSAYS  ON  TUBERCULOUS  DISEASE.  In 
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•HLETCHER'S  NOTES  FROM  NINEVEH,  AND  TRAVELS  IN  MESO- 
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FOX  ON  DISEASES  OF  THE  STOMACH.  Publishing  in  the  Medi- 
cal News  and  Library  for  1873  and  1874. 

FLINT  (AUSTIN).  A  TREATISE  ON  THE  PRINCIPLES  AND 
PRACTICE  OF  MEDICINE.  Fourth  edition,  thoroughly  revised 
and  enlarged.  In  one  large  8vo.  volume  of  1070  pages.  Cloth,  $6  ; 
leether,  raised  bands,  $7.  (Just  issued.) 

A  PRACTICAL  TREATISE,  ON  THE  PHYSICAL  EXPLORA- 
TION OF  THE  CHEST,  AND  THE  DIAGNOSIS  OF  DISEASES 
AFFECTING  THE  RESPIRATORY  ORGANS.  Second  and  revised 
edition.  One  8vo.  vol.  of  595  pages.  Cloth,  $4  50. 

A  PRACTICAL  TREATISE  ON  THE  DIAGNOSIS  AND  TREAT- 
MENT OF  DISEASES  OF  THE  HEART.  Second  edition,  enlarged. 
In  one  neat  8vo.  vol.  of  over  500  pages,  $4  00. 

-  MEDICAL  ESSAYS.     In  one  neat  12mo.  volume.     Cloth,  $1  38. 
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FOWNES  (GEORGE).  A  MANUAL  OF  ELEMENTARY  CHEMISTRY. 
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857  pages,  with  197  illustrations.  Cloth,  $2  75  ;  leather,  $3  25. 

FULLER  (HENRY).  ON  DISEASES  OF  THE  LUNGS  AND  AIR 
PASSAGES.  Their  Pathology,  Physical  Diagnosis,  Symptoms  and 
Treatment.  From  the  second  English  edition.  In  one  8vo.  vol. 
of  about  500  pages.  Cloth,  $3  50. 

GALLOWAY  (ROBERT).  A  MANUAL  OF  QUALITATIVE  AN- 
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$2  50.  (Lately published.) 

GLUGE  (GOTTLIEB).  ATLAS  OF  PATHOLOGICAL  HISTOLOGY. 
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University  of  Pennsylvania,  &c.  In  one  vol.  imperial  quarto,  with 
320  copper  plate  figures,  plain  and  colored.  Cloth,  $4. 

GREEN  (T.  HENR^).  AN  INTRODUCTION  TO  PATHOLOGY  AND 
MORBID  ANATOMY.  In  one  handsome  8vo.  vol.,  with  numerous 
illustrations.  Cloth,  $2  50. 

GIBSON'S  INSTITUTES  AND  PRACTICE  OF  SURGERY.  IntwoSvo. 
vols.  of  about  1000  pages,  leather,  $6  50. 

GRAY  (HENRY).  ANATOMY,  DESCRIPTIVE  AND  SURGICAL. 
A  new  American,  from  the  fifth  and  enlarged  London  edition.  In  one 
large  imperial  8vo.  vol.  of  about  900  pages,  with  462  large  and 
elaborate  engravings  on  wood.  Cloth,  $6;  leather,  $7.  (Jiist  issued.) 

GRIFFITH  (ROBERT  E.)  A  UNIVERSAL  FORMULARY,  CON- 
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ING OFFICINAL  AND  OTHER  MEDICINES.  Third  and  Enlarged 
edition.  Edited  by  John  M.  Maisch.  In  one  large  8vo.  vol.  of  800 
pages,  double  columns.  Cloth,  $4  50  ;  leather,  $5  50. 

GROSS  (SAMUEL  D.)  A  SYSTEM  OF  SURGERY,  PATHOLOGICAL, 
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A  PRACTICAL  TREATISE  ON  FOREIGN  BODIES  IN  THE 

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ELEMENTS  OF  PATHOLOGICAL  ANATOMY.  Third  edition. 

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GUERSANT  (P.)  SURGICAL  DISEASES  OF  INFANTS  AND  CHIL- 
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HUDSON  (A.)  LECTURES  ON  THE  STUDY  OF  FEVER.  1  vol. 
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HEATH  (CHRTSTOPHEB).  PRACTICAL  ANATOMY  ;  A  MANUAL 
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volume  ;  with  247  illustrations.  Cloth,  $3  50  ;  leather,  $4. 

HARTSHORNE  (HENRY).  ESSENTIALS  OF  THE  PRINCIPLES 
AND  PRACTICE  OF  MEDICINE.  Fourth  and  revised  edition. 
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CONSPECTUS  OF  THE  MEDICAL   SCIENCES.      Comprising 

Manuals  of  Anatomy,  Physiology,  Chemistry,  Materia  Medica,  Prac- 
tice of  Medicine,  Surgery,  and  Obstetrics.     Second  Edition.     In  one 
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HAMILTON  (FRANK  H.)  A  PRACTICAL  TREATISE  ON  FRAC- 
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Cloth,  $5  75;  leather,  $6  75. 

HOLMES  (TIMOTHY).  A  MANUAL  OF  PRACTICAL  SURGERY. 
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HOBLYN  (RICHARD  D.)  A  DICTIONARY  OF  THE  TERMS  USED 
IN  MEDICINE  AND  THE  COLLATERAL  SCIENCES.  In  one 
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HODGE  (HUGH  L.)  ON  DISEASES  PECULIAR  TO  WOMEN,  IN- 
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$14. 

HOLLAND  (SIR  HENRY).  MEDICAL  NOTES  AND  REFLECTIONS. 
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Cloth,  $3  50. 

HODGES  (RICHARD  M.)    PRACTICAL  DISSECTIONS.    Second  edi- 
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HUGHES     SCRIPTURE    GEOGRAPHY     AND    HISTORY,   with    12 
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HORNER  (WILLIAM  E.)  SPECIAL  ANATOMY  AND  HISTOLOGY. 
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1000  pages,  containing  300  wood-cuts.  Cloth,  $6. 

HILL  (BERKELEY).  SYPHILIS  AND  LOCAL  CONTAGIOUS  DIS- 
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HI LLIER  (THOMAS).  HAND-BOOK  OF  SKIN  DISEASES.  Second 
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750  pages,  with  397  illustrations.     Cloth,  $3  50. 

JONES  (C.  HANDFIELD).  CLINICAL  OBSERVATIONS  ON  FUNC- 
TIONAL NERVOUS  DISORDERS.  Second  American  Edition.  In 
one  8vo.  vol.  of  348  pages.  Cloth,  $3  25. 

KIRKES  (WILLIAM  SENHOUSE).  A  MANUAL  OF  PHYSIOLOGY. 
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many  illus.,  12mo.  Cloth,  $3  25;  leather,  $3  75.  (Lately  issued.} 

ENAPP  (F.)  TECHNOLOGY ;  OR  CHEMISTRY,  APPLIED  TO  THE 
ARTS  AND  TO  MANUFACTURES,  with  American  additions,  by 
Prof.  Walter  R.  Johnson.  In  two  8vo.  vols.,  with  500  ill.  Cloth,  $6. 

KENNEDY'S  MEMOIRS  OF  THE  LIFE  OF  WILLIAM  WIRT.  In 
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LEA  (HENRY  C.)  SUPERSTITION  AND  FORCE  ;  ESSAYS  ON  THE 
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AND  TORTURE.     Second  edition,  revised.     In  one  handsome  royal 

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STUDIES  IN  CHURCH  HISTORY.     The  Rise  of  the  Temporal 

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AN  HISTORICAL   SKETCH   OF   SACERDOTAL  CELIBACY 

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of  602  pages.     Cloth,  $3  75. 

LA  ROCHE  (R.)  YELLOW  FEVER  IN  ITS  HISTORICAL,  PATHO- 
LOGICAL, ETIOLOGICAL,  AND  THERAPEUTICAL  RELA- 
TIONS. In  two  8vo.  vols.  of  nearly  1500  pages.  Cloth,  $7. 

PNEUMONIA,   ITS   SUPPOSED    CONNECTION,    PATHOLO- 


GICAL AND  ETIOLOGICAL,  WITH  AUTUMNAL  FEVERS.     In 

one  8vo.  vol.  of  500  pages.     Cloth,  $3. 

T  INCGLN  (D.  F.)     ELECTRO-THERAPEUTICS.     A  Condensed  Man- 
J-"    ual  of  Medical  Electricity.     In  one  neat  royal  12mo.  volume,  with 

illustrations.     Cloth,  $1  50.      (Just  issued.) 

TEISHMAN  (WILLIAM).     A  SYSTEM  OF  MIDWIFERY.     Includ- 
J-1     ing  the  Diseases  of  Pregnancy  and  the  Puerperal  State.    In  one  large 

and  very  handsome  8vo.  vol.  of  700  pages  and  182  illus.     Cloth,  $5  ; 

leather,  $6. 

TATJRENCE  (J.  Z.)   AND   MOON  (ROBERT  C.)      A   HANDY-BOOK 
J-J     OF  OPHTHALMIC   SURGERY.      Second  edition,   revised   by   Mr. 

Laurence.     With  numerous  illus.     In  one  8vo.  vol.     Cloth,  $2  75. 
T  EHMANN  (C.  G.)     PHYSIOLOGICAL  CHEMISTRY.    Translated  by 
J-l     George  F.  Day,  M.  D.     With  plates,  and  nearly  200  illustrations. 

In  two  large  8vo.  vols.,  containing  1200  pages.     Cloth,  $6. 
A    MANUAL   OF   CHEMICAL   PHYSIOLOGY.     In   one   very 

handsome  8vo.  vol.  of  386  pages.     Cloth,  $2  25. 

T  AWSON  (GEORGE).   INJURIES  OF  THE  EYE,  ORBIT,  AND  EYE- 
-LJ     LIDS,  with  about  100  illustrations.     From  the  last  English  edition. 

In  one  handsome  8vo.  vol.     Cloth,  $3  50. 

T  UDLOW   (J.  L.)     A   MANUAL  OF  EXAMINATIONS  UPON  ANA- 
•LJ     TOMY    PHYSIOLOGY,  SURGERY,  PRACTICE  OF   MEDICINE, 

OBSTETRICS.  MATERIA  MEDICA,  CHEMISTRY,  PHARMACY, 

AND  THERAPEUTICS.     To  which  is  added  a  Medical  Formulary. 

Third  edition.     In  one  royal  12mo.  vol.  of  over  800  pages.     Cloth, 

$3  25  ;  leather,  $3  75. 


8  HENRY  C.  LEA'S  PUBLICATIONS. 

T  YNCH  (W.  F.)     A  NARRATIVE  OF  THE  UNITED  STATES  EX- 
-Ll     PEDITION  TO  THE  DEAD  SEA  AND  RIVER  JORDAN.     In  one 

large  and  handsome  octavo  vol.,  with  28  beautiful  plates  and  two 

maps.     Cloth,  $3. 
Same  Work,  condensed  edition.    One  vol.  royal  12tno.    Cloth,  $1. 

TAYCOCK    (THOMAS).     LECTURES   ON   THE    PRINCIPLES   AND 
-U     METHODS  OF  MEDICAL  OBSERVATION  AND  RESEARCH.    In 

one  12mo.  vol.     Cloth,  $1. 

T  YONS  (ROBERT  D.)     A  TREATISE  ON  FEVER.     In  one  neat  8vo. 
-Ll     vol.  of  362  pages.     Cloth,  $2  25. 

MARSHALL  (JOHN).  OUTLINES  OF  PHYSIOLOGY,  HUMAN 
AND  COMPARATIVE.  With  Additions  by  FRANCIS  G.  SMITH, 
M.  D.,  Professor  of  the  Institutes  of  Medicine  in  the  University  of 
Pennsylvania.  In  one  8vo.  volume  of  1026  pages,  with  122  illustra- 
tions. Strongly  bound  in  leather,  raised  bands,  $7  50.  Cloth,  $6  50. 

MACLISE  (JOSEPH).  SURGICAL  ANATOMY.  In  one  large  im- 
perial quarto  vol.,  with  68  splendid  plates,  beautifully  colored;  con- 
taining 190  figures,  many  of  them  life  size.  Cloth,  $14. 

MEIGS  (CHAS.  D  ).  WOMAN :  HER  DISEASES  AND  THEIR  REM- 
EDIES. Fourth  and  improved  edition.  In  one  large  8vo.  vol.  of 
over  700  pages.  Cloth,  $5  ;  leather,  $6. 

ON  THE  NATURE,  SIGN  S,  AND  TREATMENT  OF  CHILD-BED 

FEVER      In  one  8vo.  vol.  of  365  pages.     Cloth,  $2. 

TV/TILLER  (JAMES) .    PRINCIPLES  OF  SURGERY.    Fourth  American, 
•"•*•  from  the  third  Edinburgh  edition.      In  one  large  8vo.  vol.  of  700 
pages,  with  240  illustrations.     Cloth,  $3  75. 

THE  PRACTICE  OF  SURGERY.     Fourth  American,  from  the 

last  Edinburgh  edition.  In  one  large  Svo.  vol.  of  700  pages,  with 
364  illustrations.  Cloth,  $3  75. 

MONTGOMERY  (W.  F.)  AN  EXPOSITION  OF  THE  SIGNS  AND 
SYMPTOMS  OF  PREGNANCY.  From  the  second  English  edition. 
In  one  handsome  Svo.  vol.  of  nearly  600  pages.  Cloth,  $3  75. 

M  TILLER  (J.)  PRINCIPLES  OF  PHYSICS  AND  METEOROLOGY. 
In  one  large  Svo.  vol.  with  550  wood-cuts,  and  two  colored  plates. 
Cloth,  $4  50. 

MIRABEATJ;  A  LIFE  HISTORY.  In  one  royal  12mo.  vol.  Cloth, 
75  cents. 

TUTACFARLAND'S  TURKEY  AND  ITS  DESTINY.     In  2  vols.  royal 
1V1  12mo.     Cloth,  $2. 

ARSH  (MRS.)  A  HISTORY  OF  THE  PROTESTANT  REFORMA- 
TION IN  FRANCE.  In  2  vols.  royal  12mo.  Cloth,  $2. 

NELIGAN  (J.  MOORE).  A  PRACTICAL  TREATISE  ON  DISEASES 
OF  THE  SKIN.  Fifth  American,  from  the  second  Dublin  edition. 
In  one  neat  royal  12mo.  vol.  of  462  pages.  Cloth,  $2  25.  (Out, 
of  print  for  the  present.} 

AN  ATLAS  OF  CUTANEOUS  DISEASES.     In  one  handsome 

quarto  vol.  with  beautifully  colored  plates,  <fec.     Cloth,  $5  50. 

ILL  (JOHN)  AND  SMITH  (FRANCIS  G.)  COMPENDIUM  OF 
THE  VARIOUS  BRANCHES  OF  MEDICAL  SCIENCE.  In  one 
handsome  12mo.  vol.  of  about  1000  pages,  with  374  wood-cuts 
Cloth,  $4;  leather,  raised  bands,  $475. 


M 


NE 


HENRY  C.  LEA'S  PUBLICATIONS. 


0 


•VTIEBUHR   (B.  G.)     LECTURES   ON    ANCIENT    HISTORY;    com- 
•*•'     prising     the     history    of    the     Asiatic     Nations,     the     Egyptians, 

Greeks,   Macedonians,   and  Carthagenians.     Translated  by  Dr.  L. 

Schinitz.     In  three  neat  volumes,  crown  octavo.     Cloth,  $5  00. 

IDLING  (WILLIAM).  A  COURSE  OF  PRACTICAL  CHEMISTRY 
FOR  THE  USE  OF  MEDICAL  STUDENTS.  From  the  fourth 
revised  London  edition.  In  one  12mo.  vol.  of  261  pp.,  with  75  illus- 
trations. Cloth,  $2. 

PAVY  (F.  W.)  A  TREATISE  ON  THE  FUNCTION  OF  DIGESTION  : 
ITS  DISORDERS  AND  THEIR  TREATMENT.  From  the  second 
London  Ed.  In  one  8vo.  vol.  of  246pp.  Cloth,  $2.  (Lately  Issued.) 
A  TREATISE  ON  FOOD  AND  DIETETICS  PHYSIOLOGI- 
CALLY AND  THERAPEUTICALLY  CONSIDERED.  In  one  neat 
octavo  volume  of  about  500  pages.  Cloth,  $4  75.  (Just  issued.) 

PARRISH  (EDWARD).  A  TREATISE  ON  PHARMACY.  With  many 
Formulas  and  Prescriptions.  Fourth  edition.  Enlarged  and  thoroughly 
revised  by  Thomas  S.  Wiegand.  In  one  handsome  8vo.  vol.  of  977 
pages,  with  280  illus.  Cloth,  $5  50  ;  leather,  $6  50.  (Just  issited.) 

pIRRIE  (WILLI 0!)      THE  PRINCIPLES  AND  PRACTICE  OF  SUR- 
J-      GERY.     In   one  handsome  octavo  volume  of  780  pages,  with   316 
illustrations.     Cloth,  $3  75. 

pEREIRA  (JONATHAN).     MATERIA'MEDICA  AND  THERAPEU- 
-L      TICS.     An  abridged  edition.     With  numerous  additions  nnd  refe- 
rences to  the  United  States  Pharmacopoeia.      By  Horatio  C.   Wood, 
M.  D.     In  one  large  octavo  volume,  of  1040, pages,  with  236  illustra- 
tions.    Cloth  $7  00;  leather,  raised  bands,  |8  00. 

pULSZKY'S  MEMOIRS  OF  AN  HUNGARIAN  LADY.     In   one  neat 
•L      royal  12mo.  vol.     Cloth,  $1. 

PAGET'S  HUNGARY  AND  TRANSYLVANIA.     In  two  royal  12mo. 

-t      vols.     Cloth,  $2. 

ROBERTS  (WILLIAM).  A  PRACTICAL  TREATISE  ON  URINARY 
AND  RENAL  DISEASES.  A  second  American,  from  the  second 
London  edition.  With  numerous  illustrations  and  a  colored  plate. 
In  one  very  handsome  8vo.  vol.  of  616  pages.  Cloth,  $4  50.  (Just 
Issued.) 

-RAMSBOTHAM   (FRANCIS   H.)     THE   PRINCIPLES  AND   PRAC- 
-Lu    TICE  OF  OBSTETRIC  MEDICINE  AND  SURGERY.     In  one  im- 
perial 8vo.  vol.  of  650  pages,  with  64  plates,  besides  numerous  wood- 
cuts in  the  text.     Strongly  bound  in  leather  $7. 

EIGBY  (EDWARD).     A  SYSTEM  OF  MIDWIFERY.     Second  Ameri- 
can edition.    In  one  handsome  8vo.  vol.  of  422  pages.     Cloth,  $2  50. 
EANKE'S  HISTORY  OF  THE  TURKISH  AND  SPANISH  EMPIRES 
in  the  16th  and  beginning  of  17th  Century.     In  one  8vo.  volume, 
paper,  25  cts. 

HISTORY  OF  THE  REFORMATION  IN  GERMANY.     Parts  I. 

II.  III.     In  one  vol.     Cloth,  $1. 

ROYLE  ( J.  FORBES).  MATERIA  MEDICA  AND  THERAPEUTICS. 
Edited  by  Jos.  Carson.  M.  D.  In  one  large  8vo.  vol.  of  about  700 
pages,  with  98  illustrations.  Cloth,  $3. 

SMITH  (EUSTACE).  ON  THE  WASTING  DISEASES  OF  CHILDREN. 
Second  American  edition,  enlarged.  In  one  8vo.  vol.  Cloth,  $2  50. 
(J\ist  Issued.) 


10  HENRY  C.  LEA'S  PUBLICATIONS. 


OMITH  (J.  LEWIS.)     A  TREATISE  ON  THE   DISEASES   OF   IN- 
to     FANCY  AND  CHILDHOOD.     Second   edition.     In   one  large  8vo. 
volume  of  over  700  pages.     Cloth,  $5  ;  leather,  $6. 

QAKGENT  (F.  W.)     ON  BANDAGING  AND  OTHER  OPERATIONS 
^     OF  MINOR  SURGERY.     New  edition,  with  an  additional  chapter 

on  Military  Surgery.     In  one  handsome  royal  12mo.  vol.  of  nearly 

400  pages,  with  184  wood-cuts.     Cloth,  $1  75. 

QHARPEY    (WILLIAM)    AND    QTJAIN    (JONES   AND   EICHARD). 

to  HUMAN  ANATOMY.  With  notes  and  additions  by  Jos.  Leidy, 
M.D.,  Prof,  of  Anatomy  in  the  University  of  Pennsylvania.  In  two 
large  8vo.  vols.  of  about  1300  pages,  with  51 1  illustrations.  Coth,  $6. 

SKEY  (FREDERIC  C.)  OPERATIVE  SURGERY.  In  one  8vo.  vol. 
of  over  650  pages,  with  about  100  wood-cuts.  Cloth,  $3  25. 

SLADE  (D.  D.)  DIPHTHERIA  ;  ITS  NATURE  AND  TREATMENT. 
Second  edition.  In  one  neat  royal  12mo.  vol.  Cloth,  $1  25. 

SMITH  (HENRY  H.)  AND  HORNER  (WILLIAM  E.)  ANATOMICAL 
ATLAS.  Illustrative  of  the  structure  of  the  Human  Body.  In  one  large 
imperial  8vo.  vol.,  with  about  650  beautiful  figures.  Cloth,  $4  50. 

SMITH  (EDWARD).  CONSUMPTION;  ITS  EARLY  AND  REME- 
DIABLE STAGES.  In  one  8vo.  vol.  of  254  pp.  Cloth,  $2  25. 

STILLE  (ALFRED).  'THERAPEUTICS  AND  MATERIA  MEDIC  A. 
Fourth  edition,  revised  and  enlarged.  In  two  large  and  handsome 
volumes  8vo.  Cloth,  $10;  leather,  $12.  (Now  ready.) 

QCHMITZ  AND  ZUMPT'S  CLASSICAL  SERIES.     In  royal  18mo. 
to     CORNELII  NEPOTIS  LIBER  DE  EXCELLENTIBUS  DUCIBUS 

EXTERARUM  GENTIUM,  CUM  VITIS  CATONIS  ET  ATTICI. 

With  notes,  <fcc.     Price  in  cloth,  60  cents;  half  bound,  70  cts. 

C.  I.  C^ESARIS  COMMENTARII  DE  BELLO  GALLICO.  With  notes, 
map,  and  other  illustrations.  Price  in  cloth,  60  cents;  half  bound, 
70  cents. 

C.  C.  SALLUSTII  DE  BELLO  CATILINARIO  ET  JUGURTHINO. 

With  notes,  map,  &c.     Price  in  cloth,  60  cents  ;  half  bound,  70  cents. 

Q.  CURTII  RUFII  DE  GESTIS  ALEXANDRI  MAGNI  LIBRI  VIII. 
With  notes,  map,  &c.  Price  in  cloth,  80  cents  ;  half  bound,  90  cents. 

P.  VIRGILII  MARONIS  CARMINA  OMNIA.  Price  in  cloth,  85 
cents;  half  bound,  $1. 

M.  T.  CICERONIS  ORATIONES  SELECTS  XII.  With  notes,  &c. 
Price  in  cloth,  70  cents  ;  half  bound,  80  cents. 

ECLOG^l  EX  Q.  HORATII  FLACCI  POEMATIBUS.  With  notes, 
&c.  Price  in  cloth,  70  cents;  half  bound,  80  cents. 

ADVANCED  LATIN  EXERCISES,  WITH  SELECTIONS  FOR 
READING.  Revised,  with  additions.  Cloth,  price  60  cents  ;  half 
bound,  70  cents. 

S WAYNE  (JOSEPH  GRIFFITHS).  OBSTETRIC  APHORISMS.  A 
new  American,  from  the  fifth  revised  English  edition.  With  addi- 
tions by  E.  R.  Hutchins,  M.  D.  In  one  small  12mo.  vol.  of  177  pp., 
with  iljustrations.  Cloth,  $1  25. 

QTURGES    (OCTAVIUS).     AN    INTRODUCTION    TO   THE   STUDY 
to     OF  CLINICAL   MEDICINE.     In  one  12mo.  vol.      Cloth,  $1   25. 
(Lately  published.) 


HENRY  C.  LEA'S  PUBLICATIONS.  11 


OCHOEDLER  (FREDERICK)  AND  MEDLOCK  (HENRY).   WONDERS 

W  OF  NATURE.  An  elementary  introduction  to  the  Sciences  of  Physics, 
Astronomy,  Chemistry,  Mineralogy,  Geology,  Botany.  Zoo'logy, 
and  Physiology.  Translated  from  the  German  by  H.  Medlock.  In 
one  neat  8vo.  vol.,  with  679  illustrations.  Cloth,  $3. 

STOKES  (W.)     LECTURES  ON  FEVER.     One  handsome  8vo.  volume. 

W     (Preparing.') 

SMALL  BOOKS  ON  GREAT  SUBJECTS.  Twelve  works ;  each  one  10 
cents,  sewed,  forming  a  neat  and  cheap  series  ;  or  done  up  in  3  vols. 
Cloth,  $1  50. 

QTRICKLAND    (AGNES).     LIVES  OF  THE  QUEENS  OF   HENRY 
£>     THE  VIII.  AND  OF  HIS  MOTHER.     In  one  crown  octavo  vol., 

extra  cloth,  SI;  black  cloth,  90  cents. 
MEMOIRS  OF  ELIZABETH,  SECOND  QUEEN  REGNANT  OF 

ENGLAND  AND  IRELAND.     In  one  crown  octavo  vol.,  extra  cloth, 

$1  40;  black  cloth,  $1  30. 

rpANNER  (THOMAS  HAWKES).    A  MANUAL  OF  CLINICAL  MEDI- 
-L     CINE  AND   PHYSICAL   DIAGNOSIS.     Third  American  from  the 

second  revised  English  edition.     Edited  by  Tilbury  Fox,  M.  D.     In 

one  handsome  12mo.  volume  of  366  pp.     Cloth,  $1  50. 

ON  THE  SIGNS  AND  DISEASES  OF  PREGNANCY.     First 

American  from  the  second  English  edition.    With  four  colored  plates 
and  numerous  illustrations  on  wood.     In  one  vol.  8vo.  of  about  500 
pages.     Cloth,  $4  25. 

rPTTKE  (DANIEL  HACK).     INFLUENCE  OF  THE  MIND  UPON  THE 
•*•     BODY.     In  one  handsome  8vo.  vol.  of  416  pp.    Cloth,  $3  25.     (Just 

issued.) 

HHAYLOR    (ALFRED    S.)     MEDICAL    JURISPRUDENCE.     Seventh 
•*•     American  edition.     Edited  by  John  J.  Reese,  M.D.     In  one  large 
8vo.  volume  of  879  pages.     Cloth,  $5 ;  leather,  $6.     (Just  issued.) 
PRINCIPLES  AND  PRACTICE   OF   MEDICAL   JURISPRU- 
DENCE.    From  the  Second  English  Edition.      In  two  large  8vo. 
vols.     Cloth,  $10;  leather,  $12.      (Just  issued.) 

ON  POISONS  IN  RELATION  TO  MEDICINE  AND  MEDICAL 

JURISPRUDENCE.     Third  American  from  the  Third  London  Edi- 
tion.    1  vol.  8vo.     (Preparing.) 

rpHOMAS  (T.  GAILLARD).     A   PRACTICAL   TREATISE  ON   THE 
J-     DISEASES  OF   FEMALES.     Fourth  edition,  thoroughly  revised. 
In  one  large  and  handsome  octavo  volume  of  801  pages,  with  191 
illustrations.     Cloth,  $5  00  ;  leather,  $6  00.     (Now  ready.) 

TODD  (ROBERT  BENTLEY) .     CLINICAL  LECTURES  ON  CERTAIN 
ACUTE  DISEASES.    In  one  vol.  8vo.  of  320  pp.,  extra  cloth,  $2  50. 
THOMPSON  (SIR  HENRY).    CLINICAL  LECTURES  ON  DISEASES 
OF  THE  URINARY  ORGANS.     Second  and  revised  edition.     In 
one  8vo.  volume,  with  illustrations.     Cloth,  $2  25.      (Now  ready.) 

THE   PATHOLOGY  AND  TREATMENT  OF  STRICTURE  OF 

THE   URETHRA  AND  URINARY  FISTULA.      From  the  third 
English  edition.    In  one  8vo.  vol.  of  359  pp.,  with  illus.    Cloth,  $3  50. 

THE  DISEASES  OF  THE  PROSTATE,  THEIR  PATHOLOGY 

AND  TREATMENT.  Fourth  edition,  revised.  In  one  very  hand- 
some 8vo.  vol.  of  355  pp.,  with  13  plates.  Cloth,  $3  75. 
WALSHE  (W.  H.)  PRACTICAL  TREATISE  ON  THE  DISEASES 
OF  THE  HEART  AND  GREAT  VESSELS.  Third  American  from 
the  third  revised  London  edition.  In  one  8vo.  vol.  of  420  pages. 
Cloth,  $3. 


12  HENRY  C.  LEA'S  PUBLICATIONS. 


WOHLER'S  OUTLINES  OF  ORGANIC  CHEMISTRY.  Translated 
from  the  8th  German  edition,  by  Ira  Remsen,  M.D.  In  one  neat 
12mo.  vol.  Cloth,  $3  00.  (Lately  issued.) 

WALES  (PHILIP  S.)  MECHANICAL  THERAPEUTICS.  In  one 
large  8vo.  vol.  of  about  700  pages,  with  642  illustrations  on  wood. 
Cloth,  $5  75 ;  leather,  $6  75. 

WELLS  (J.  SOELBERG).  A  TREATISE  ON  THE  DISEASES  OP 
W  THE  EYE.  Second  American,  from  the  Third  English  edition,  with 
additions  by  I.  Minis  Hays,  M.D.  In  one  large  and  handsome  octavo 
vol.,  with  6  colored  plates  and  many  wood-cuts,  also  selections  from 
the  test-types  of  Jaeger  and  Snellen.  Cloth,  $5  00  ;  leather,  $6  00. 
(Lately  issued.) 

WHAT  TO  OBSERVE  AT  THE  BEDSIDE  AND  AFTER  DEATH 
IN  MEDICAL  CASES.  In  one  royal  12mo.  vol.  Cloth,  $1. 
WATSON  (THOMAS).  LECTURES  ON  THE  PRINCIPLES  AND 
PRACTICE  OF  PHYSIC.  A  new  American  from  the  fifth  and  en- 
larged English  edition,  with  additions  by  H.  Hartshorne,  M.D.  In 
two  large  and  handsome  octavo  volumes.  Cloth,  $9  ;  leather,  $11. 
(Lately  essued.) 

WEST  (CHARLES).     LECTURES  ON  THE  DISEASES  PECULIAR 
W   TO  WOMEN.     Third  American  from  the  Third  English  edition.     In 

one  octavo  volume  of  550  pages.     Cloth,  $3  75  ;  leather,  $4  75. 
LECTURES  ON  THE  DISEASES  OF  INFANCY  AND  CHILD- 
HOOD.    Fifth  American  from  the  sixth  revised  English  edition.     In 
one  large  8vo.  vol.  of  670  closely  printed  pages.     Cloth,  $4  50  ;  lea- 
ther, $5  50.     (Now  ready.) 

ON   SOME    DISORDERS    OF    THE   NERVOUS   SYSTEM   IN 

CHILDHOOD.     From  the  London   Edition.     In  one   small  12mo. 
volume.     Cloth,  $1.  * 

AN  ENQUIRY  INTO  THE  PATHOLOGICAL  IMPORTANCE 

OF  ULCERATION  OF  THE  OS  UTERI.  In  one  vol.  8vo.  Cloth, 
$1  25. 

WILLIAMS  (CHARLES  J.  B.)  PULMONARY  CONSUMPTION: 
ITS  NATURE,  VARIETIES,  AND  TREATMENT.  In  one  neat 
octavo  volume.  Cloth,  $2  50.  (Lately  pub  Used.) 

WILSON  (ERASMUS).  A  SYSTEM  OF  HUMAN  ANATOMY.  A 
new  and  revised  American  from  the  last  English  edition.  Illustrated 
with  397  engravings  on  wood.  In  one  handsome  8vo.  vol.  of  over 
600  pages.  Cloth,  $4  ;  leather,  $5. 

ON  DISEASES  OF   THE   SKIN.     The  seventh  American  from 

the  last  English  edition.     In  one  large  8vo.  vol.  of  over  800  pages. 
Cloth,  $5. 

Also,  A  SERIES  OF  PLATES,  illustrating  "Wilson  on  Diseases  of  the 
Skin,"  consisting  of  20  plates,  thirteen  of  which  are  beautifully 
colored,  representing  about  one  hundred  varieties  of  Disease.  $5  50. 

Also,  the  TEXT  AND  PLATES,  bound  in  one  volume.  Cloth,  $10. 

THE  STUDENT'S  BOOK  OF  CUTANEOUS  MEDICINE.  In 

one  handsome  royal  12mo.  vol.  Cloth,  $3  50. 

WINSLOW  (FORBES).  ON  OBSCURE  DISEASES  OF  THE  BRAIN 
AND  DISORDERS  OF  THE  MIND.  In  one  handsome  8vo.  vol. 
of  nearly  600  pages.  Cloth,  $4  25. 

•nrriNCKEL  ON  DISEASES  OF  CHILDBED.    Translated  by  chad- 

*•   wick.     (Preparing.) 

IVEISSL     ON    VENEREAL     DISEASES.       Translated     by    Sturgis. 
*-J    ( Prepa  ri  ng . ) 


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